A LIPO-GEL REACTION. 235 



shown that it can be obtained with products from a large number 

 of organs and tissues. But as the reaction occurs in nature it 

 may be said to be specific, for the follicular fluid under natural 

 conditions does not meet any other fluid with which it produces 

 a coagulum except spermatozoa. It has been shown that the 

 reaction does not occur with peritoneal fluid, smear of the mucosa 

 of the genital tract, or urine. The reaction is produced with 

 lipoids but the only lipoid with which the follicular fluid would 

 ordinarily come in contact is that accompanying the spermatozoa. 



We may next discuss the possible physiological purpose of 

 this coagulation phenomenon. At first sight the phenomenon 

 appears to be of a paradoxical nature. In order to perform their 

 function of fertilizing the egg the spermatozoa must retain their 

 motility when introduced into the genital tract; yet it appears 

 from my experiments that in the genital tract they meet a fluid, 

 namely, the follicular fluid, which destroys their motility. 1 With- 

 out discussing this matter at too great length the following 

 explanations of the utility of the reaction may be suggested. 



i. Lillie has shown that the eggs of certain invertebrates 

 contain and produce a substance which he designates as fertilizin 

 which has the property of activating and agglutinating the 

 spermatozoa and is of importance in the fertilization of the egg. 

 If fertilizin is produced by the mammalian egg it would certainly 

 occur in the follicular fluid. I could not determine the place of 

 origin of the substance in the follicular fluid which gives the 

 coagulating reaction with spermatozoa. It might originate from 

 the ovum, or the granulosa cells. My experiments (p. 230) indi- 



1 It is very surprising that in the whole literature one can not find the slighest 

 indication of this phenomenon. A tremendous number of workers have tried the 

 reaction upon spermatozoa of different kind of substances excepting the follicular 

 fluid and this seems the most logical substance to be tried. Professor Lillie was 

 the first to try this reaction and thus opened an entirely new field of experimentation. 

 The origin of the whole question concerning the lipo-gel reaction is included in the 

 long series of works published by Professor Frank R. Lillie. Compare, e.g., 

 "Studies in Fertilization. V. Mechanism of Fertilization in Arbacia," The Jonni. 

 oj Exp. Zoo/., Vol. 16, 1914, p. 523: ".Studies on Fertilization. V. The Behavior 

 of the Spermatozoa of Nereis and Arbacia with Special References to Egg-extrac- 

 tives," The Journ. of Exp. Zool., 1913, Vol. 14. As a general review of the entire 

 problem in which my work must be integrated see Frank R. Lillie, "Problems of 

 Fertilization," Univ. of Chicago Piess. One can find there also a very rich litera- 

 ture concerning the subject. 



