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A STUDY OF THE FUNCTION OF THE EPIDIDYMIS

III. FUNCTIONAL CHANGES UNDERGONE BY SPERMATOZOADURING THEIR PASSAGE THROUGH THE EPIDIDYMIS AND

VAS DEFERENS IN THE GUINEA-PIG

BY WILLIAM C. YOUNG.

(Arnold Biological Laboratory, Brown University.)

(Received zist September, 1930.)

(With One Text-figure.)

INTRODUCTION.

IN two recent papers (Young, 1929 a, b) attention was directed to the fact that,in mammals, spermatozoa which appear to have attained their full structuraldevelopment while still attached to the germinal epithelium, are compelled to passthrough the long coiled ductus epididymidis before they reach the vas deferenswhere they are in a position to be discharged. It was noted further that, while thesignificance of the epididymis for spermatozoa and the nature of changes undergoneby spermatozoa during their passage through this organ have been subjects ofexperimentation by numerous investigators, current opinions with respect to thesequestions are both numerous and varied.

Among other opinions, the suggestions had been made (1) that certain develop-mental changes which are important for the successful functioning of spermatozoaare attributable to some specific action of the epididymal secretion (Tournade,1913; Stigler, 1918; Braus and Redenz, 1924; Redenz, 1924, 1925 a, b, 1926;von Lanz, 1924 b, 1926), and (2) that the epididymis is a reservoir functioning topreserve the vitality of spermatozoa stored in it until the time of their discharge(Van der Stricht, 1893; Tournade and Delacarte, 1913; Braus and Redenz, 1924;Redenz, 1924, 1925 a, b, 1926; von Lanz, 1924 a, b, 1926). These opinions havesince been reaffirmed and extended (von Lanz and Malyoth, 1928; von Lanz,1929; Redenz, 1929; Redenz and Belonoschkin, 1929; and Belonoschkin, 1929 a, b).

What appeared to be a defect in the first of these theories was the fact thatcertain developmental changes, such as the acquisition of the capacity for beingstimulated to motion and, to some extent, the increased capacity for resisting hightemperature, which are undergone by spermatozoa during their passage throughthe epididymis, represent nothing more than a continuation of changes which areoccurring while the spermatozoa are still contained in the testis (Young, 1929 a).Such being the case, it seemed unnecessary to postulate the existence of somestimulus to spermatozoon development in the epididymis which is not present in

152 WILLIAM C. YOUNG

the testis. The second theory, to the effect that the epididymis functions to preservethe vitality of spermatozoa until the time of their discharge, was questioned afterit had been found that any preserving action possessed by the epididymal secretionis powerless to prevent the ageing of spermatozoa which normally seems to followthe attainment of their maturity (Young, 1929 b).

Because of these objections to the older conceptions of the epididymal spermato-zoon relationship, a new theory was formulated as far as this was possible on thebasis of the experiments which had been performed. It was suggested that theepididymis provides an environment in which stimuli to spermatozoon develop-ment which are not different from those found in the testis are present; that sperma-tozoa require more time for the completion of their development than they havebefore they are loosened from the germinal epithelium; that they are, therefore,carried into the epididymis as immature or unripe cells which are incapable offunctioning; and that much of the time consumed by them in passing through theepididymis is necessary for the completion of their development. Once functionalmaturity has been attained, however, there is no influence which preserves themindefinitely and, unless they are discharged, they age and become at first incapableof effecting fertilisation and finally incapable of being stimulated to motion. Inother words, it was suggested (1) that the developmental changes which occur inspermatozoa during their passage through the epididymis are not conditioned bysome specific action of the epididymal secretion, but are inherent in the protoplasmof the spermatozoa themselves, and (2) that emphasis should be shifted from theconception of the epididymis as a spermatozoon reservoir acting to preservespermatozoa which have attained a certain level of development in a state of staticmaturity to the conception of the epididymis as an organ of spermatozoon develop-ment in which these cells are constantly changing; ripening until an optimal func-tional capacity is attained and then ageing if their residence is prolonged.

As indicated in a brief, preliminary communication (Young and Simeone, 1930),confirmation and extension of these suggestions have come from two groups ofexperiments. The first involved a study of the reproductive capacity of spermatozoaremoved from two different levels of the epididymis of the guinea-pig under normaland experimental conditions. A description of the methods which were employedalong with an enumeration of the results which were obtained, and a discussionof the application of these results to the problem as a whole, form the contents ofthis paper.

The second group of experiments involved an investigation of the fate of non-ejaculated spermatozoa. The observations made during this part of the study arereported elsewhere (Simeone and Young, 1931).

EXPERIMENTAL.The changes which occur in the reproductive capacity of spermatozoa as they

pass through the epididymis were determined by means of the artificial inseminationof females with spermatozoa from two levels of the epididymis under normal andexperimental conditions. If it is true, as has been supposed, that spermatozoa

A Study of the Function of the Epididymis 153

enter the epididymis as immature cells which ripen and acquire their capacity foreffecting fertilisation as they pass through this organ, the percentage of fertileinseminations when younger spermatozoa from the proximal end of the epididymisare used should be less than the percentage of fertile inseminations when olderspermatozoa from the distal end are used.

';'.:X\£~- '•'y--$'&~ •'•=•'&':??: '•;

Fig. i. Testis, epididymis, and proximal end of vas deferens from guinea-pig as seen when retractedinto the abdominal cavity, a.. .b is line of separation of cauda epididymidis into proximal and distalportions from which younger and older spermatozoa respectively were removed from normal males.Lines c, d, and e represent location of ligatures in experimental males.

The procedure which was employed in testing this hypothesis was as follows:Whenever two or more females came into heat simultaneously the epididymidesfrom a normal male were separated along the line a.. .b, Fig. i. Each part was thenmacerated in a quantity of Locke's solution so selected that the densities of theresulting spermatozoon suspensions would be as nearly equal as possible. A lightether anaesthesia was then administered to the females to be inseminated, andapproximately f c.c. of the suspension introduced into the body of the uterus bymeans of a glass catheter. In this way one female was inseminated with spermatozoafrom the proximal end of the cauda epididymidis, and the other with spermatozoa


from the distal end of the cauda epididymidis from the same male. The females^were then held ventral side up for 5 minutes, after which they were numbered andplaced in cages reserved for experimental animals. From the fifteenth to thetwentieth days inclusive after the insemination, each female was examined twicedaily for rupture of the vaginal closure membrane or other signs of a recurrentoestrum. If such had not occurred by the twentieth day, the female was regardedas pregnant and kept isolated until the end of the gestation period, at which timethe size and condition of the litter were noted. Any irregularities such as still-births, abortions, and intra-uterine resorptions were also recorded.

At the time of insemination samples of the spermatozoon suspensions wereexamined microscopically. It is of interest, in connection with a point to bementioned later that, without exception, the spermatozoa removed from the distalend exhibited a more vigorous motion than those removed from the proximal end.

Ninety-nine females were inseminated with spermatozoa removed from theproximal portion of the cauda epididymidis, and ninety-seven were inseminatedwith spermatozoa removed from the distal portion. Of the former, thirty-three, or33'3 Pe r cent., were impregnated. Of the females inseminated with spermatozoafrom the distal end, sixty-six, or 68 per cent., were impregnated. The doubling ofthe number of fertile inseminations, when spermatozoa from the distal portionof the epididymis were used, may be attributable either to the greater maturity ofspermatozoa from the distal end or to the maturity of a much larger number ofspermatozoa from this portion of the epididymis. In either case the difference isbelieved to provide ample evidence for the developmental nature of changes whichoccur in spermatozoa during their passage through the epididymis. The opinionthat these changes are inherent in the spermatozoa rather than conditioned by somespecific action of the epididymal secretion has been expressed. Additional evidencewill be cited elsewhere in the paper.

The suggestion (Young, 1929 b) that spermatozoa within the epididymis whichhave attained an optimal functional maturity are not preserved indefinitely, butsoon begin to undergo regressive or degenerative changes, was tested by a modifica-tion of the above described procedure.

Following an abdominal incision and the retraction of the testis and epididymisinto the body cavity, it was possible to ligature the head of the epididymis in oneplace, c, and the vas deferens in two places, d and e, without interfering with thevascularisation of the structures involved. The testes were then replaced in thescrotal sacs. Provided no adhesions developed, the males were killed 20 and 25days later, and spermatozoa removed from the proximal and distal ends of the caudaepididymidis as before. At this time samples of the spermatozoon suspensionswere examined microscopically.

It was found that the condition of the tubules 20 or 25 days after the operationis never similar to that at the time of the operation, provided the ligature of thehead of the epididymis has been complete. Most of the tubule proximal to theline a.. .b has been emptied, and the portion of the tubule distal to the line a.. .bhas become conspicuously distended with spermatozoa which have been forced


Pnto it from the proximal levels. Despite this condition it is easily possible to removespermatozoa from the proximal and distal portions of the column without the con-tamination of either.

It was expected, if the course of changes undergone by spermatozoa duringtheir residence in the epididymis is similar to that which had been postulated, thatthe younger spermatozoa contained in the proximal end of the cauda epididymidisat the time of the operation would mature, develop the capacity for a more vigorousmotion and become more capable of effecting fertilisation. Similarly, it was ex-pected that the older, mature or ripe spermatozoa contained in the distal end ofthe cauda epididymidis at the time of the operation would age, become weakenedin their capacity for being stimulated to motion, and become less capable of effectingfertilisation. In short, it was expected that the conditions with respect to thestrength of motility and the capacity for effecting fertilisation would be reversedfrom what they had been when spermatozoa from normal males were used.

Forty-three females were inseminated with spermatozoa from the proximal endof the spermatozoon column, and forty were inseminated with spermatozoa fromthe distal end of the column. Of the former, nineteen, or 44-2 per cent., were im-pregnated. Of the females inseminated with spermatozoa from the distal end ofthe column, thirteen, or 32-5 per cent., were impregnated. In most cases, spermatozoaremoved from the proximal end of the column were as active or conspicuouslymore active than those from the distal end of the column. As was expected, there-fore, spermatozoa which have been isolated in the epididymis for 20 days showa reversal of the conditions which exist in the normal epididymis. Spermatozoaat the proximal end of the column can be stimulated to a more vigorous motion,and are more successful in effecting fertilisation after 20 days' isolation in theepididymis than those from the distal end of the column in the same animals.

This reversal of the normal relationship was even more striking in the case ofspermatozoa which had been isolated 25 days. In this part of the experiment ninety-eight females were inseminated with spermatozoa from the proximal end of thecolumn, and one hundred females were inseminated with spermatozoa from thedistal end of the column. Of the former, forty-eight, or 49 per cent., were im-pregnated. Of the females inseminated with spermatozoa from the distal end ofthe column, twenty-five, or 25 per cent., were impregnated.

The data described above are summarised in the two upper lines of Table I.Based upon actual reproductive capacity, which is unexcelled as a measure of generalfitness, they reveal more clearly than any data obtained heretofore the course ofchanges which can occur in spermatozoa during their residence in the epididymis.Developmental changes culminating in the attainment of an optimal condition foreffecting fertilisation are the first to occur. They are followed by regressive changeswhich result in a loss of the capacity for effecting fertilisation. Proof that develop-mental changes occur came from the fact that the younger spermatozoa removedfrom the proximal end of the epididymis were successful in effecting fertilisationin but 33-3 per .cent, of the cases, while older spermatozoa removed from the distalend of epididymides from the same males were successful in effecting fertilisation


in 68 per cent, of the cases. Further proof came from the fact that the ability or'the younger spermatozoa to effect fertilisation increased from an approximatenormal of 33-3 per cent., under the conditions of the experiment, to 44-2 per cent,at the end of 20 days' isolation in the epididymis and to 49 per cent, at the end of25 days' isolation. Proof that regressive changes set in following the attainment ofan optimal functional capacity came from the fact that the ability of the maturespermatozoa located in the distal end of the epididymis to effect fertilisation de-creased from an approximate normal of 68 per cent., under the conditions of theexperiment, to 32*5 per cent, following 20 days' isolation in the epididymis andto 25 per cent, following 25 days' isolation.

Table I. Summary of data obtained following insemination of females with spermatozoaremoved from proximal and distal ends of normal and ligatured cauda epididymides.

Number of inseminationsFertile inseminations (%)Average litter sizeNumber of normal indi-

Number of still-born indi-viduals

Number of aborted and re-sorbed individuals

Still-born individuals (%)Aborted and resorbed indi-

viduals (%)

Normal males (control)

Proximalend

99

33'3

1-8548

7

2

12-3

3 6

Distalend

97

6 8 0

2 6 0

139

13

15

7-8

9 0

20-day

Proximalend

43

44-22 5 0

32

2

10 ±

4 8

22-7

ligature

Distalend

40

32'52-S8

23

2 ±

6

8 2

2O-O

25-day

Proximalend

98

4 9 0

2-3472

9

21 ±

9'420-9

ligature

Distalend

1 0 0

25-0

2-36

43

6

9 ±

10-7

18-8

Whether or not the fertilising capacity of spermatozoa from the proximal endof the column would have increased further, and that of spermatozoa from thedistal end of the column would have decreased further with 30 days' isolationis not known. It is planned to determine this in an extension of the investiga-tion.

That the reversal of the spermatozoon relationships referred to above was notmore complete at the end of 25 days may be attributable to certain factors whichcould not be controlled, namely, a constant interchanging and shifting in positionof spermatozoa within the epididymis. Whether or not there is any active motionof spermatozoa within the epididymis which might be partly responsible for thisis not known, although Redenz and von Lanz claim that spermatozoa within theepididymis are capable of independent motion. It may be instead that youngerspermatozoa are constantly being forced into the distal part of the epididymis andvas deferens to mix with the older spermatozoa by the distally directed muscularpressure. In addition, the removal of old spermatozoa in the epidjdymis and vasdeferens by liquefaction, which is now known to occur there (Simeone and Young,


I931), may leave places which are filled by viable spermatozoa from the proximalregions of the tubule.

An observation of interest, in connection with the suggestion that the develop-ment of spermatozoa which takes place during their passage through the epididymisis inherent in their protoplasm rather than conditioned by simuli originating inthe epididymis, was made on the testes removed from certain males 20-25 daysafter the ligature of the head of the epididymis. Many such testes containednumerous patches of white seminiferous tubules which bore a striking resemblanceto the small portion of the tubule of the cauda epididymidis proximal to the linea.. .b in the figure. When these white tubules were removed, macerated in Locke'ssolution, and studied microscopically, they were found to contain many activespermatozoa. This condition was in marked contrast to that found in the semini-ferous tubules from a normal testis, where only an occasional spermatozoon canbe stimulated to exhibit the weakest flagellation of its tail. It is, however, similarto that found in the testis of the albino rat (Young, 1929 a), where many spermatozoacapable of being stimulated to motion can be found.

It is suggested that the great increase in the number of such spermatozoa whichcan be stimulated to motion and the great increase in the strength of their motilityare attributable to the greater maturity of these cells which have been unable topass from the testis into the epididymis. Presumably, their development has con-tinued despite their retention in the testis. The observation that this continuationof development is not dependent upon the passage of the spermatozoa into theepididymis provides further evidence against the idea of a specific action of theepididymal secretion on spermatozoon development. The extent to which sperma-tozoa isolated in the testis in this manner can develop is not known.

The data (Table I) which have to do with litter size and condition are meagre,since only 204 of the 477 inseminated females were impregnated. They are pre-sented, however, for what they suggest in the way of future experiments ratherthan for any conclusions which may be drawn from them at this time.

Average litter size was smallest, 1-84, among that group of females inseminatedwith the youngest spermatozoa, namely, those from the proximal end of the caudaepididymidis from normal males. It rose to 2-60, when older spermatozoa fromthe distal end of the cauda epididymidis were used. It remained near this level,2-50 and 2-58, when spermatozoa which had been isolated 20 days were used, anddecreased slightly to 2-34 and 2*36 when spermatozoa which had been isolated25 days were used. In experiments which are now in progress an attempt is beingmade to determine if the smaller litters, which seem to follow inseminations withthe youngest and oldest spermatozoa, are attributable to the fertilisation of a smallernumber of ova or to an unusually large number of intra-uterine resorptions.

The number of still-born individuals on the one hand, and the number ofindividuals aborted or resorbed within the uterus on the other hand, were recordedseparately. The percentage of still-born individuals will be noted to be fairlyconstant throughout, and as high among the females inseminated with the youngestspermatozoa as among those inseminated with the oldest spermatozoa. The per-

jEB-vmii 11


centage of individuals which were aborted or resorbed, on the other hand,somewhat lower, 3-6 and 9 per cent., among the controls than it was, 18-8 to 22-7per cent., when the older spermatozoa were used. It is of interest to note that manyof these individuals showed gross structural defects.

The question arises: is this larger number of abortious cases of intra-uterineresorption and foetal abnormalities which occurred following the insemination offemales with the older spermatozoa due to the age of the spermatozoa which wereused ? Imperfect development has been suggested as a consequence of the fertilisa-tion of the eggs of certain invertebrates by old spermatozoa (Dungay, 1913, forNereis; Medes, 1917, for Arbacia), but whether this also applies to the guinea-pigcan be determined only after more data have accumulated from experiments nowin progress.

The uniform frequency with which still-born individuals were born to femalesin all groups compared with the variation in the frequency with which abortionsand intra-uterine resorptions occurred, suggests that these gestational abnormalitiesmay be two different phenomena traceable to different causes rather than beingexpressions of the same phenomenon differing only in the time of occurrence.The still-births may be a consequence of parturitional difficulties associated,possibly, with the size of the foetus or its position within the uterus. Abortionsand intra-uterine resorptions may have, on the other hand, a germinal origin.Again, it is expected that experiments which are now being undertaken, will disposeof this problem one way or another.

DISCUSSION.

The data which have been obtained from the experiments described above andfrom earlier experiments (Young, 1929 a, b) furnish a basis for an evaluation of thedivergent theories of the epididymal spermatozoon relationship held by contem-porary workers (Rendenz, von Lanz, Belonoschkin, and Young, loc. cit.).

Redenz and Belonoschkin seem to be of the opinion that all internal or proto-plasmic changes undergone by spermatozoa during their development, occur whilethese cells are still attached to the germinal epithelium. These changes include thedevelopment of the capacity for independent motion. The spermatozoa are thenloosened from the germinal epithelium, and swim by means of their own strengththrough the rete tubules and vasa efferentia into the ductus epididymidis. At thistime the spermatozoa are mature internally, but unprotected externally from theeffects of injurious factors in the environment, such as acids and high temperature,which act to decrease the intensity and duration of motion. As they pass throughthe epididymis, however, they become enclosed in a microscopically invisible pro-tective envelope {Oberfldchenhdutchen or Hulle) composed of epididymal secretion.This adherent layer of secretion provides the external protection they require, andthus imparts to them a greater resistance against the action of injurious factorswhich they may encounter. In other words, Rendenz and Belonoschkin wouldseem to be of the opinion that the ripeness or maturity attained by spermatozoa


during their passage through the epididymis is a quality conditioned by the presenceof the epididymal secretion around the spermatozoon, and is not a developmentinherent in the spermatozoon.

An equally important part of their theory concerns the provision made for thepreservation of spermatozoon vitality until the time of an ejaculation. This is saidto be accomplished by the limitation of the ability for independent motion whichspermatozoa contained in the epididymis are assumed to possess, a condition whichprevents the dissipation of the energy available for motion in useless movements.This limitation of motion, in turn, is thought to be accomplished by some actionof the high carbon dioxide tension and the low oxygen tension which are con-sequences of the density of the stored spermatozoa. Restoration of the motilecondition is believed to be brought about at the time of an ejaculation, possiblyby the oxygenation which occurs, and possibly by the alkalinity of the prostaticand seminal vesicle secretions with which the spermatozoa become mixed.

In only one place does Redenz (1926, p. 135) suggest that the vitality of sperma-tozoa may not be preserved indefinitely.

Der Begriff "Reifung" hat aber noch einem anderen Inhalt. Nachdem ich zugleichmit v. Lanz mit ganz verschiedenen Methoden feststellen konnte, dass der Nebenhodenein Organ ist, das lebende Samenfaden speichern kann, ist die Frage, in welchem Zeit-punkt das Spermium nach seiner Entstehung zur Befruchtung kommt, von wesentlicherBedeutung geworden. Es ist damit zum erstenmal die Frage angeschnitten, welchenEinfluss auf die Bewegungsdauer, auf die Zeugung, ja auch auf die Vererbung und dieGeschlechtsbestimmung eine solche Uberreife im mannlichen Organ hat. Zwar werdenSpermien, die sehr lange im Nebenhodenschweif verweilen, hochstwahrscheinlich auchan ihrem Sekretmantel Schaden leiden und damit weniger Aussichten haben, zur Be-fruchtung zu gelangen. Jedenfalls ist zu der Frage des Eialters, bei der Befruchtung,vom Follikelsprung angerechnet, die des Spermienalters, gemessen von der Abstossungaus der Sertolizelle an, hinzugetreten.

This suggestion does not seem to be incorporated in the theory of the functionof the epididymis expressed in more recent papers, however, and it is difficult toconclude how much importance he attaches to it.

The most recent theory of the epididymal spermatozoon relationship advancedby von Lanz (1929) is similar in many respects to that formulated by Redenz. Likethe latter, von Lanz is of the opinion that spermatozoa move out of the testis bymeans of their own motion, that important ripening changes occur during theirpassage through the epididymis in consequence of some specific action of theepididymal secretion, and that the preservation of spermatozoon vitality during theresidence of these cells in the epididymis is accomplished by the limitation of theirmotion. Unlike Redenz, he believes that a considerable buffering action of theepididymal secretion must be carried over to the protoplasm of the spermatozoonduring storage in the epididymis, that ripening events take place inside the cellprotoplasm and not around it, that the limitation of motion is accomplished by thenatural acidity of the epididymal secretion rather than by any excess of carbondioxide or deficiency of oxygen, and in no place does he suggest that spermatozoonvitality may not be preserved indefinitely.


Many observations made in the course of experiments performed by the writerare at variance with certain of the more important assumptions and conclusionswhich are a part of the theories of the epididymal spermatozoon relationshipadvanced by Redenz and von Lanz. It is doubtful, first of all, on the basis of manyobservations on testes from bulls and rams (Young, 1929 a), if spermatozoa exhibitan independent motion while they are still contained within the seminiferous tubules,or take any active part in their movement into the epididymis. Only the weakestvibratile movement of the tail has ever been detected by the writer following themaceration of testis fragments in Locke's solution, a flagellation which has neverbeen observed to result in progressive motion. Furthermore, spermatozoa removedfrom distal parts of the epididymis are activated more quickly than those removedfrom proximal levels. If spermatozoa do move into the epididymis by means oftheir own strength, and if their motion is limited gradually by the nature of theenvironment found within this organ, one would expect that spermatozoa in thedistal end of the structure where their motion is most completely limited, wouldbe the last rather than the first to be activated. The nature of the epididymalsecretion may be such as to prevent the occurrence of motion, but it probably doesnot limit motion which once existed.

A second point emphasised by Redenz and von Lanz, which is questioned onthe basis of data reported previously (Young, 1929 a) and in this paper, is thatdevelopmental changes undergone by spermatozoa during their passage throughthe epididymis are conditioned by some specific action of its secretion. It has beenfound, for example, that the extent to which spermatozoa removed from the semini-ferous tubules can be stimulated to motion varies from species to species. In apreparation from the testis of the rat, hundreds of motile spermatozoa can be seen.In preparations from the testes of the bull, ram, and guinea-pig, on the other hand,only an occasional spermatozoon, which exhibits the weakest vibratile movementof the tail, can be seen. Evidently, in some species under normal conditions, acertain portion of the developmental process occurs only after the spermatozoahave been carried into the epididymis, whereas, in other species, correspondingchanges occur while the spermatozoa are still within the testis.

It has also been observed that the number of spermatozoa which can be stimu-lated to motion, following their removal from the testis, is often much greater whenthe escape of spermatozoa from the testis has been prevented by the ligature of thehead of the epididymis than it is when the testis is normal. From this it wouldseem, that in any given animal, many of the developmental changes which normallyoccur after the spermatozoa have entered the epididymis will occur while these cellsare still contained in the testis, if their passage from the testis into the epididymisis prevented.

If the above described observations have been interpreted correctly, the olderconception of spermatozoon development as consisting of two processes, one ofwhich occurs in the testis and the other of which occurs only in the epididymis,seems questionable. It is suggested instead, that spermatozoon development is asingle continuous process occurring in part in the testis and in part in the epididymis,


and that the extent to which development occurs in the testis or in the epididymisdepends, not upon one set of stimuli in the testis and upon another set in theepididymis, but rather upon the proportion of the total developmental period spentin each of the two organs.

A third criticism of the theories advanced by Redenz and von Lanz is thatneither makes proper allowance for the fact noted elsewhere (Young, 1929 b, andothers) and in this paper, that regressive as well as developmental changes mayoccur in spermatozoa during their passage through the epididymis. Inclusion ofthis fact in any theory of the epididymal spermatozoon relationship is important,not only to complete the account of the post-testicular history of spermatozoa,but also because certain problems are raised which otherwise would be overlooked,and which may prove of some importance for the part played by the male in repro-duction.

What would appear to be the most important of these centre around the rateof progress of spermatozoa through the epididymis, viz. how much time is requiredfor the passage of spermatozoa through the epididymis? To what extent does thisrate of progress vary from male to male? To what extent is it modified by thefrequency of copulation and by other factors? Do differences exist in the physio-logical condition of discharged mammalian spermatozoa similar to those noted byLillie (1915) and by Goldforb (1929 a, b, c, and earlier papers) in sea-urchinspermatozoa? If such differences exist in mammalian spermatozoa, can they berelated to differences in the rate of passage of spermatozoa through the epididymis ?Lastly, if such differences exist in discharged mammalian spermatozoa, are theyimportant for any reproductive qualities of the male mammal?

Most of these questions are now being investigated, and it is expected that theanswers, when such are obtained, will supplement the theory of the epididymalspermatozoon relationship elaborated in this and the following paper (Simeoneand Young, 1931).

CONCLUSIONS.

1. By means of experiments which have involved the artificial insemination offemale guinea-pigs with spermatozoa removed from different levels of the ductusepididymidis and observations on spermatozoa confined in the seminiferous tubules,further evidence has been obtained for the conclusion (1) that the time consumedby spermatozoa in passing through the epididymis is necessary for a completionof their development, (2) that the changes undergone during this period representa continuation of changes which start while the spermatozoa are still attached tothe germinal epithelium, and are not conditioned by some specific action of theepididymal secretion, and (3) that in case the spermatozoa are not discharged orlost in some other manner, regressive or degenerative changes follow the attainmentof an optimal functional capacity.

2. Evidence has been obtained for the existence of a constant distally directedcurrent of spermatozoa through the epididymides of males even in the absence


of copulations. The importance of determining this rate of progress of spermatozoathrough the epididymis is emphasised on account of its possible relationship tothe physiological condition of ejaculated spermatozoa.

3. The greater frequency with which abortions and intra-uterine resorptionsoccurred among females inseminated with older spermatozoa has been noted, aswas the fact that several of the foetuses lost in this manner showed gross structuraldefects.

REFERENCES.

BELONOSCHKIN, B. (1929 a). Zeitschr.f. Zellforsch. u. mikrosk. Anat. 9, 643-662.(1929 b). Zeitschr.f. Zellforsch. u. mikrosk. Anat. 9, 750—753.

BRAUS, H. and REDENZ, E. (1924). Anat. Anz. 58, 121-131.DUNGAY, N. S. (1913). Biol. Bull. 25, 213-261.GOLDFORB, A. J. (1929 a). Biol. Bull. 57, 333-349.

(1929 b). Biol. Bull. 57, 350-388.(1929 c). Biol. Bull. 57, 389-411.

VON LANZ, T. (1924 a). Verh. d. anat. Gesellsch. 33, 106-115.(1924 b). Zeitschr.f. Anat. u. Ent.-geschichte, 74, 761-815.(1926). Zeitschr.f. Anat. u. Ent.-geschichte, 80, 177-282.(1929). Pfluger's Arch. 222, 181-214.

VON LANZ, T. and MALYOTH, G. (1928). Pfluger's Arch. 218, 535-552.LILLIE, F. R. (1915). Biol. Bull. 28, 229-251.MEDES, G. (1917). Journ. Morph. 30, 317—432.REDENZ, E. (1924). Arch.f. mikrosk. Anat. u. Ent.-mech. 103, 593-628.

(1925 a). Verh. d. anat. Gesellsch. 34, 180-189.(1925 b). Arch.f. Ent.-mech. d. Organ. 106, 290-302.(1926). Wurzburger Abhandlungen aus dem Gesamtgebiet der Medizin, Neue Folge, 4, 107-150.(1929). Zeitschr.f. Zellforsch. u. mikrosk. Anat. 9, 734-749.

REDENZ, E. and BELONOSCHKIN, B. (1929). Zeitschr.f. Zellforsch. u. mikrosk. Anat. 9, 663-682.SIMEONE, F. A. and YOUNG, W. C. (1931). Journ. Exp. Biol. 8.STIGLER, R. (1918). Pfluger's Arch. 171, 273-282.TOURNADE, A. (1913). C.R. Soc. Biol.n, 738-739.TOURNADE, A. and DELACARTE, J. (1913). C.R. Soc. Biol. 74, 861-862.VAN DER STRICHT, O. (1893). C.R. Soc. Biol. 45, 799-801.YOUNG, W. C. (1929 a). Journ. Morph. and Physiol. 47, 479-495.

(1929 b). Journ. Morph. and Physiol. 48, 475-491.YOUNG, W. C. and SIMEONE, F. A. (1930). Proc. Soc. Exp. Biol. and Med. 27, 838-841.

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