and Laboratory Methods. 



1361 



other changes were also observed. After twenty-four hours it was common to 

 find several free heads and tails, their number increasing daily, until by the fourth 

 day it was often difficult to find a perfect spermatozoon ; yet these, when present, 

 showed evidence of marked degeneration, and their reaction to staining was not 

 constant. 



Staining was accomplished by the various anilin dyes, of which carbol- 

 fuchsin was found to be of most value, therefore the accompanying illustrations 

 were sketched from specimen slides stained by carbol-fuchsin. In examining 

 specimens stained in 1899, I find that the tail is the first to give up its stain, 

 and from one-fourth to one-seventh of the tails of the spermatozoa of the sheep 

 and rats show no stain, and are seen with difficulty. Fading was noted to take 

 place earlier where methylen blue was employed. In but one instance, that of 

 the mouse, was it necessary to apply heat in order to stain the spermatozoa. 



Measurements were made by the use of both the stage and eye-piece microm- 

 eters, always measuring the entire length, dimensions of head, and length of 

 tail ; the latter being markedly altered whenever the staining was imperfect. It 

 was thought to be of possible service to have all measurements recorded both in 

 millimeters and in inches. All measurements and sketches were made with a 

 1-6 objective and 2 eye-piece. In the sketching no attempt was made to preserve 

 the original size of the cells. The total lengths given were obtained by the 

 measuring of complete cells, recording the greatest and smallest measurements 

 only; while the measurements of the heads and tails were often taken after these 

 parts had separated. Therefore the total length is not always equivalent to 

 the sum of the lengths of the head and tail. 



Fig. 1.— Man. 



Fig. 2.— Dog (Mastiff). 



The spermatozoa of man (Fig. 1) were found to stain deeply with carbol 

 fuchsin ; the heads and tails were equally stained, and appeared more distinct 

 and uniform than did those from any other member of this series. The tail was 

 seldom found to be coiled or twisted, except where water had been previously 



