STUDIES ON CYTOLYSINS 81 



4. CONCLUSIONS 



It seems legitimate to infer from the foregoing experiments 

 on rabbits and mice that lens tissue of such forms when injecited 

 into fowls excites the production of specific antibodies which 

 may attack in utero the lenses of the young of the species used 

 as antigen. This reaction is not invariable, however, since, so 

 far as one can determine by direct observation, a majority or 

 even all of the individuals of a litter may not be acted upon, 

 or a given individual may be affected in only one eye. The 

 reason for such uneven effects is not apparent. It occurs to 

 one, at first thought, that possibly the placenta is impervious 

 to such antibodies except as occasional rupture of placental 

 blood-vessels might permit of direct mingling of fetal and ma- 

 ternal blood. But such an hypothesis does not account for the 

 fact that only one eye of an individual may be affected. More- 

 over, it seems improbable that mere accident to the placenta 

 would account for such closely similar results as were found in 

 both mice and rabbits. 



The liquefactions described would indicate a true cytolytic 

 effect. Of the several proteins composing the lens, one is 

 fibrous, and it is upon this that the sensitized serum seems to 

 have operated. Whether or not it had also affected the other 

 ingredients could not be determined. 



Whether the clouding and opaquing which occurred in others 

 of the lenses should be regarded as the result of a cytolysin 

 or of a precipitin is problematical. Further experiments are 

 necessary to clear up this point. The important fact is that 

 such opacity can be induced by specific sera and that it may be- 

 come permanent. The most striking case among the rabbits 

 would indicate that if the opacity is attributable to a precipitin 

 reaction, a cytolytic effect accompanied it. For in this instance 

 the affected lens has remained so reduced in size that the whole 

 eye has been markedly dwarfed. 



In so far as the literature on cytolysins records positive re- 

 sults, it leads one to expect specific effects in the immediate 

 animal injected. But as already noted, no such effects were 



THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 26, NO 1 



