232 GREGOR T. POPA. 



to dry, the droplets run together into larger and larger drops 

 which are also refractile and homogeneous. Their appearance 

 is very similar to that of a fatty substance. 



These droplets persist in normal hydrochloric acid but dis- 

 solve in sodium hydroxide (0.9 per cent.). When treated with a 

 saturated solution of Sudan III. in 96 per cent, alcohol, all of the 

 droplets turn red and appear as bright red points. These facts 

 indicate the lipoid nature of the droplets. 



The final analysis of this substance is a task for the chemist. 

 The important fact in connection with these experiments is that 

 the spermatozoa are always accompanied by a variable quantity 

 of a lipoid substance. 1 This lipoid substance is responsible for 

 the reaction with which this paper is concerned. The lipoid is 

 in the state of a colloidal sol. When mixed with salt solution 

 its state of dispersion is gradually changed but it still remains in 

 the sol state. Upon the addition of follicular fluid, the thermo- 

 labile substance in this fluid exerts an influence upon the lipoid 

 changed by salt solution and causes it to pass into the gel state. 

 A coagulum is thus formed. Because of these characteristics of 

 the reaction, I have designated the latter as a lipo-gel reaction. 



The question to be next considered is whether the lipoid 

 substance which surrounds the spermatozoa is specific for the 

 reaction as is the thermolabile substance present in the follicular 

 fluid. An article of Kolliker's suggested to me that the lipoid 

 accompanying the spermatozoa might be similar in nature to 

 myelin, 2 found in the central nervous system. I therefore mixed 

 follicular fluid with a cell-free extract obtained by grinding up 

 spinal cord (cow) in salt solution in a mortar and filtering. The 



solution upon lipoids was observed also by Runnstrom, J., "\\eitere Studien iiber 

 die Verenderungen der Lipoide bei der befruchtung Seeigeleies," Arch. Zoo/., 16, 

 1924, p. i. The same effect was obtained instead of NaCl solution with thymol 

 by Bidermann, W., "Uber Wesen und Bedeutung der Protoplasma lipoide," 

 P finger's Archiv, Bd. 202, 1924, p. 223. 



1 The same idea of a substance surrounding the spermatozoa is considered by 

 Braus-Redenz and Redenz, H. E., Nebenhoden u. Samenfaden. Anat. Anz. Erg. 58, 

 1924, p. 121-131. But these authors merely postulate that such a substance exists 

 and give no evidence concerning its nature. As regards the role of this hypothet - 

 ical substance, the study of Redenz does not touch the essential meaning of it 

 because the nature of the substance is not explained. 



2 A. Kolliker, " Phisiologische Studien iiber die Samenflussigkeit," Zeitschr. fur 

 wiss. Zoo!., Bd. VII., 1856, p. 201. 



