490 HENEAGE GIBBES. 



spermatozoon of the horse, as shown in Fig. 4, and of that 

 of the guinea-pig. Fig. 5. 



In these spermatozoa there is an intermediate part 

 between the head and tail, and on it the filament is 

 seen plainly, but beyond this it is very indistinct. 



In Reptilia I have only as yet examined the spermatozoon 

 of the green lizard and slow worm, and in both of these I 

 have found the filament, but very indistinct, and requiring a 

 high magnifying power. 



The speramatozoon oi Lacerta virtdis in the fresh state has 

 a very peculiar appearance. The part corresponding to the 

 elliptical body in the Amphibia is enveloped in a gelatinous 

 mass somewhat resembling a leucocyte; it keeps in con- 

 stant motion for a long time, and it is almost impossible to 

 see any other part of it until it loses its vitality; the gela- 

 tinous mass keeps changing its shape as it moves with a 

 quick jerky motion. 



After a number of experiments in staining the sperma- 

 tozoa of Mammals with several dyes, I found it almost 

 impossible to obtain any such definite results as in the case 

 of the larger spermatozoa of the Amphibia, and it occurred 

 to rae to try to attain the same result, viz. to show differences 

 in chemical constitution of the different parts of the sperma- 

 tozoon, by observing the effect produced by different acids and 

 alkalies of varying strengths. 



I obtained the most striking result with a solution of 

 chloride of sodium, varying from | to 5 per cent ; with this 

 reagent I found that the head gradually dissolved away, 

 together with the membrane connecting the filament to the 

 body. 



In Figs. 6, 7, 8, and 9 the effect of the chloride of sodium 

 is shown 



Taking a solution of § per cent, strength at the end of 

 twenty-four hours, the head will be found in different stages 

 of disintegration ; some heads are not affected in the least, 

 others are partially dissolved, while still others have become 

 so faint as scarcely to be discerned. After another twenty- 

 four hours, quite one half of the head will have altogether 

 disappeared, but at the same time some heads will remain 

 almost untouched. 



The same result may be arrived at in a much shorter time 

 by using a stronger solution. 



It will be seen, by referring to Figs. 7 and 8, that 

 the elliptical structure, the long filament, and the body, 

 remain intact. 



In the spermatozoon of L. viridis, the gelatinous mass 



