330 O P H T H A L M I C R E S E A R C H

uveal tract, albino uveal tract, and spleen. (There was no difference between animals which developed uveitis, and animals which did not.) The spleen-controlled animals were positive to: (1) pigmented uveal tract, (2) albino uveal tract, (3) spleen, (4) whole blood. The adjuvant controls remained nega­tive to all skin tests.

Seven experimental uveal tract animals demon­strated precipitin lines on agar diffusion (antigen: pigmented uveal tract) . However, these tests were equally divided between those animals with and without uveitis.

In interpreting the skin tests, it would seem that both the uveal tract experimental and spleen con­trol groups were sensitive to an antigen common to both spleen and uveal tract but not present in whole blood. This antigen is probably unrelated to the experimental uveitis, insofar as there was no dis­tinction between animals with uveitis and those without. (Also shown on agar diffusion.) There­fore, it would seem as if there is a common tissue antigen in those tissues tested, which obscures the antigen-antibody reaction related to uveitis produc­tion. This would tend to discourage further at­tempts to localize a uveitis-producing antibody with an impure antigen mixture (homologous uveal tract).

Electrophoretic characteristics of hyaluronidase, subtilin and carbonic anhydrase compared to lacrimai proteins. Olive F. Erickson, M.D., Rachel Hatlen and Margaret H. Berg, Presby­terian Medical Center, Stanford University Medi­cal School, San Francisco, and Palo Alto. Hyaluronidase, subtilin and carbonic anhydrase

are three of the some 550 know enzymes. The ac­tions of these three are consistent with tear con­stituents. Electrophoresis was done with a phos­phate buffer of p H 7.0, barbitol 8.6, and LKB 8.9.

Hyaluronidase mobility lies between gamma globulin and lysozyme in all three buffers. Electro-phoretically our "slow lysozyme" could be hyalu­ronidase. Many patients who do not secrete this pro­tein are troubled with a mucous tear film. Some who have been stimulated by cholinergic drugs to secrete "slow lysozyme" seem to have a more nor­mal tear. Electrophoretically and clinically, "slow lysozyme" could be hyaluronidase.

Subtilin was described by Linderstrom-Lang who found that albumin was altered electrophoretically and microscopically when exposed to enzymes from B-subtilus. In normal tears albumin is different from blood serum albumin. Subtilin did not go into solution readily. A 10-percent solution showed a very small concentration and the major protein band was in the gamma zone.

Carbonic anhydrase was made up into 1.0 and 5.0-percent solutions and electrophoresis studies were done with the same buffer solutions. Large concentrations overlapped both gamma and beta zones. The center of the peak in all three buffers was about midway between gamma and beta and a second small peak at about alpha one. Electro­

phoretically carbonic anhydrase could be present in tears. Lacrimai proteins in this zone are particularly increased in glaucoma patients who still have evi­dence of lacrimai proteins. Many patients with glaucoma, however, have sicca patterns. One of the tests for carbonic anhydrase is a shift in pH. Clinically the pH 7.2 to 8.8 Schirmer test paper shows a greater pH shift in the patients who have only conjunctival secretions. Hyaluronidase, subtilin and carbonic anhydrase show mobility rates that are found in lacrimai secretions. Further studies are warranted to identify tear film proteins to confirm or rule out the presence of these important enzymes.

A study of cross-eyed Siamese cats. Jane E. Hyde, Ph.D., Department of Physiology, University of California Medical Center, Los Angeles. In three Siamese cats with demonstrated con­

stant concomitant strabismus, terminal experiments with electrical stimulation in encéphale isole prep­arations revealed markedly increased convergence in response to bilateral occipital cortical stimulation. In contrast, five non-Siamese cats and one Siamese with intermittent cross-eyes, similarly stimulated, yielded conjugate ocular movement to a vertical position with no convergence. Other evidences of innervational abnormality were detected in the cross-eyed cats by stimulation of brainstem areas. No abnormality in size of extraocular muscles or nerves could be seen. Histologie examination re­vealed normal development of abducens and ocul­omotor nuclei. Two of the three cross-eyed cats had additional mechanical restriction to abduction, revealed in part by pitting of the infraorbital plate; such defect was not seen in the third cross-eyed or in noncross-eyed Siamese or non-Siamese cats.

Thus, anatomic defects of orbital structures were not consistently associated with innervational or neurogenic abnormalities observed in strabismic Siamese cats.

Accommodation and applanation tonometry. Man-sour F . Armaly, M.D., and Melvin L. Rubin, M.D., Department of Ophthalmology, State Uni­versity of Iowa, Iowa City. The applanation tonometer of Goldmann was

used to investigate the effect of accommodation on intraocular pressure. A special fixation apparatus was used which could control the accommodative stimulus and could provide a check on sustained accommodation of the subject. Ten subjects were used: five, aged 20 to 25 years, and five, aged 45 to 55 years. In all experiments one eye was used consistently for fixation ; the other eye for pressure measurements. Applanation tonometric readings were made on the non-fixing eye at intervals of one minute and continuing for at least 20 min­utes. The effect of the following conditions on in­traocular pressure was explored: (1) Complete relaxation, (2) controlled, graded accommodation, (3) the change in fixation from distance (18 feet) to the near fixation light of the Haag-Streit slit-

OPHTHALMIC RESEARCH 331

lamp, (4) the modification of the effect of the above conditions by age, and three pharmacologie agents: 10-percent phenylephrine, 1.0-percent Cyclogyl, and 1.0-percent atropine.

The results indicate that there is a definite re­duction of intraocular pressure associated with ac­commodation in all subjects ; the reduction averages 3.6 mm. Hg. In the younger age group, the intra­ocular pressure reduction was significantly greater in magnitude and shorter in its time constant than in the older age group. This decrease in intraocular pressure is exactly comparable to the drop occurring on use of the near fixation light. This intraocular pressure response is not affected in any way by 10-percent neosynephrine and is essentially com­pletely eliminated by the cycloplegics used.

During complete relaxation of accommodation for distance fixation, repeated applanation readings reveal no effect of tonometry itself on the intraocu­lar pressure. In every case the first reading was slightly but significantly higher on the first reading than in all subsequent readings. The difference be­tween the first and the following readings during relaxation was completely eliminated by parasym-patholytic drugs.

The results must be explained by the effect of accommodation on the various parameters deter­mining the steady-state pressure (that is, episcleral venous pressure, outflow facility, and/or inflow rate) and not by intra- or extraocular changes of a transitory nature (as extraocular muscles or intra­ocular blood volume).

OPHTHALMIC MINIATURE

Dr. Bigger exhibited to the meeting two rabbits, one of which had been treated with the bichloride of mercury, the other had been left to nature ; in the latter case nine months had elapsed since the performance of the operation (corneal transplantation) ; in the former, only ten weeks. These animals, as has been already stated, were the subject of his first and last experiments at home, and were calculated to show the improvement made in the mode of performing the operation. The difference between them was very remarkable. The eye to which the bichloride of mercury had been applied, seemed to possess a distinct and perfect power of vision ; and there was nothing to indicate the existence of a transplanted cornea, but a slight line in the situation of the cicatrix, and some degree of coni-cality in the cornea. To enable himself and the meeting to judge more ac­curately of the power of vision in this animal, Dr. Bigger had destroyed the opposite eye. In the other animal the vision was very imperfect, not so much from opacity of the cornea, as from the condition of the iris and the deeper-seated tissues of the eye. The cixatrix in this case was large, dense, and of a somewhat triangular form.

Dr. Bigger on "Transplanting of the cornea," The Dublin Journal of Medical Science, 1837.