108 THE AMERICAN NATURALIST [Vol. LV 



The crystalline lens of the rabbit was selected as 

 antigen, and fowls as the source of the antibodies. The 

 lenses of newlv killed rabbits were pulped thoroughly 

 in a mortar and diluted with normal saline solution. 

 About four cubic centimeters of this emulsion was then 

 injected intraperitoneally or intravenously into each 

 of several fowls. Four or five weekly treatments with 

 such lens-emulsions were given. Then a week or ten 

 days after the last injection the blood-serum of one or 

 more of the fowls was used for injection into pregnant 

 rabbits. The rabbits had been so bred as to have the 

 young advanced to about the tenth day of pregnancy, 

 since from the tenth to the thirteenth day seems to be a 

 particularly important period in the development of the 

 lens. It is then growing rapidly and becomes surrounded 

 by a rich vascular network that later disappears. From 

 four to seven cubic centimeters of the sensitized fowl- 

 serum were injected intravenously into the pregnant 

 rabbits at intervals of two or three days for from ten 

 days to two weeks. Several rabbits died from the treat- 

 ment and many young were killed in utero. Of sixty- 

 one surviving young from mothers thus treated, four 

 had one or both eyes conspicuously defective and five 

 others had eyes which were clearly abnormal. It is pos- 

 sible that still others were more or less affected, since 

 wo judged only by obvious, visible effects. We found 

 later in some of the descendants of these individuals that 

 rabbits which passed for normal during their earlier 

 months subsequently manifested traces of defects in their 

 lenses or in other parts of the eye. 



The commonest abnormality seen in both the original 

 subjects and in their descendants was partial or com- 

 plete opacity of the lens, usually accompanied by reduc- 

 tion in size. Other defects were cleft iris, persistent 

 hyaloid artery, bluish or silvery color instead of the 

 characteristic red of the albino eye, microphthalmia and 

 even almost complete disappearance of the eyeball. 

 Taking into account the method of embrj^ological devel- 



