23 



lating the streptococci. The growth of other organisms was by 

 no means hindered by the procedure, for one tube from eacii 

 organ was often left unseaKxl. Incubation was at ol'^ C, and the 

 routine method of examining the tubes was identical with the 

 method of Carpenter (9). 



Whenever possible, a sample of blood was obtained from the 

 animal either before, or at the time of slaughter, for agglutination 

 wuh Bact. aburtum antigen. Extracts from the semnial vesicles, 

 testes, and epididymes were injected into the guinea pigs and 

 examined at the end of four to six weeks for the presence of 

 Bad. ahortum. 



Sections of all organs were fixed as soon as possible in either 

 Zenker's or Ilelly's fluid. Hematoxylin and eosin were used as 

 routine tissue stains. Eosin and methylene blue, and Mallory's 

 connective tissue stain Avere, however, frequenth' utilized for 

 special staining reactions. 



The motility of the spermatozoa is best observed about half an 

 hour after ejaculation, when the thick tenacious clot has started 

 to liquefy. A drop of the fluid is placed upon a warmed slide, 

 preferably one with a slight depression in it. and observation 

 made with high or low powered objectives. The semen may be 

 examined whole, or diluted with physiological saline .solution. In 

 the latter ease, the sperms have a greater opportunity for freedom 

 of motion in the absence of the thick viscid coagulate. A small 

 vial erf saline solution may be carried in one's pocket where it 

 will be kept warm, and a drop of this placed upon the glass slide. 

 If the clot of semen is merely touched to this drop on the slide, 

 plenty of .spermatozoa will be deposited for an examination. This 

 method is very satisfactory for the observation of motility, but 

 needless to say, the undiluted semen must be used for the deter- 

 mination of the number of sperms present. If necessary, the 

 specimen may be covered with a cover glass and the oil immersion 

 objective used. While a warmed slide is quite sufficient to enable 

 one to detect the i^resenee of motility, the field soon cools and the 

 sperms gradually become less motile. If possi])le. it is best to 

 use a small electrically heated stage warmer, which keeps the 

 field at a constant ])ody temperature, so that the duration of the 

 motion may be observed for hours if warmed jihysiological saline 

 solution is added as the fluid evaporates. 



Stained preparations are best made with fhin smears on the 

 glass slides. This is conveniently done by placing a drop of the 

 semen on a slide and smearing it over the surface with the edge 

 of another slide. A fairly thin and even field is thus obtained. A 

 .still better method is to first dilute the semen with physiological 

 saline solution, so as to ol)tain fewer sperms in the field. After 

 drying the pre]>aration in air. fixation may l)e produced by draw- 

 ing the slide through a gas flame several times, by immersion in 

 equal parts of alcohol and ether, or even 1)y the use of tissue fixers 

 such as Ilellv's or Zenker's .fluids. For ordinary .staining, heat 



