STUDIES ON CYTOLYSINS — SPERMATOTOXINS 211 



in spermatotoxic foAvl serum. The spermatozoa in the spermato- 

 toxic serum were largely immobihzed at the end of ten minutes, 

 and wholly so at the end of thirty minutes. The spermatozoa 

 in normal fowl serum were still active at the end of an hour, 

 when a gradual slowing down of motiUty set in. The spermato- 

 zoa in normal saline solution were moving about with undi- 

 minished activity at the end of three hours, when observations 

 were discontinued. 



To each of two test-tubes, one of which contained 2 cc. of 

 spermatotoxic serum and the other 2 cc. of normal fowl-serum, 

 a cubic centimeter of normal rabbit spermatozoa in normal 

 salt solution was added. The tubes were then placed in an 

 incubator at 38°C. and examined twenty-four hours later. The 

 spermatozoa in the normal serum, though iimiiobile, were intact; 

 those in the sensitized serum were much fragmented, particularly 

 tails and heads were separated as if a very soluble or digestible 

 point existed in the region of the middle-piece. The same 

 phenomena were observed in hanging-drop preparations similarly 

 left over night. Also, there had been a very marked agglutina- 

 tion of the spermatozoa in the spermatotoxic serum. There 

 had been some agglutination, though not so much, in the normal 

 serum. 



On March 4th the foregoing tests were repeated with the 

 serum of the second sensitized fowl, with practically the same 

 results. 



On March 11th similar tests were made with the serum of the 

 third sensitized fowl. This serum proved to be more active 

 than that of the other two fowls. In a mixture of 1 part of the 

 sensitized serum and 1 part normal salt solution the spermato- 

 zoa of a normal rabbit were practically all immobilized by the 

 end of five minutes, although some were still ahve at the end of 

 an hour in a similar dilution of normal fowl serum. Various 

 other dilutions were tried, as 1 part senmi to 2, 3, and 4 parts of 

 normal saline solution, respectively. In the l-to-3 dilution 

 of spermatotoxic serum the spermatozoa were immobile at 

 the end of ten minutes; in the l-to-4 dilution slight motion was 



