220 M. F. GUYER 



17th. A microscopical examination of the fresh semen showed 

 that the spermatozoa were reduced in number and that many 

 of them were immobile. Normal spermatozoa were immo- 

 bilized in the serum of 32A1 in three and a half hours, although 

 they were still active in normal serum at the end of twenty-four 

 hours. The spermatozoa of 32A1 in his own serum were immo- 

 bile at the end of two and one-half hours; in normal serum, at 

 the end of four and one-half hours. 



From the foregoing experiments it is evident that not only 

 does the blood serum become toxic for spermatozoa as the 

 result of intravenous injections of the animal's own spermatozoa, 

 but the living spermatozoa of such treated males also are affected 

 in some way, since they are much less viable, even in normal 

 serum, than are the spermatozoa of the untreated males. It 

 was reasoned that this might be due to a specific effect in vivo 

 of the spermatotoxic serum on the spermatozoa in question, 

 or it might be simply the result of a general lowering of the 

 animal's vitality, due to the introduction of considerable quanti- 

 ties of a foreign or an unaccustomed protein into the blood stream. 

 To test this point spermatozoa from a male (90A2) which had 

 received several intravenous injections of tjrphoid vaccine, 

 followed by two heavy intravenous injections of living typhoid 

 germs, were employed. The blood of this male was at its 

 highest titre for the Widal reaction when used in the present 

 experiment, March 3rd. For the test equivalent quantities of 

 the spermatozoa of the male (90A2) treated with typhoid germs, 

 the male (32 Al) with spermatotoxic serum, and a normal male 

 (4A8) were taken. In the spermatotoxic blood-serum of 32A1, 

 his own spermatozoa were all immobilized at the end of twenty 

 hours, but the spermatozoa of the other two males still showed 

 some activity at the end of thirty hours, when observations were 

 discontinued. In the serum of the normal rabbit the spermato- 

 zoa of 32A1 showed but little activity at the end of twenty hours, 

 while those of the other two males were still active and remained 

 so for hours. In the serum of 90A2, the rabbit treated with 

 typhoid germs, the respective results with the three sets of 

 spermatozoa were the same as in normal serum. Obviouslj^, the 



