294 ON THE RESTORATION OF THE MOTIONS OF 



in a well-marked manner, but in this case care is still more 

 requisite than with more dilute solutions. 



The above phenomenon is witnessed not only in the Mam- 

 malia in which I first observed it, but also in the Amphibia, 

 except that in the latter (Frog) far more dilute solutions of 

 caustic alkalies are required to produce it, the spermatic fila- 

 ments of these animals being much mtore readily destroyed 

 than those of the Mammalia. As respects the Birds and 

 Fishes, my observations in these classes are not concluded. 



When the action of caustic alkalies upon the spermatic 

 filaments is observed farther, it is obvious that they are 

 powerful excitants, not only in concentrated solutions, but 

 that they also exert an influence in dilute solutions also. If a 

 solution of sugar, which does not affect the movements of the 

 spermatic filaments, be mixed with a small quantity of caustic 

 potass, so as to make a solution containing 1-1000 to 1-5000 

 of the alkali, it will be seen that a fluid of this kind not 

 only maintains the motions of the filaments for hours together, 

 but that it renders them even more lively than in the pure 

 syrup itself, so that it would seem as if very weak alkaline 

 fluids of a certain strength are the most favourable to the 

 movement of the spermatic filaments. 



On the Eestoration of the Motions of the Spermatozoids 

 of the Mammalia. By MM. Moleschott and J. C. 

 KiCCHETTI. (Comptes rendus, No. 13, Mars 26, 1855.) 



The author's researches were made on the spermatozoids of 

 the Bull, taken in each experiment from the epididymis. 

 These spermatozoids have a lynx-shaped head, the depression 

 in which is small and situated towards the inferior third, and 

 a very long tail, furnished with a minute appendicular 

 nodosity, which is soluble in the alkalies, and is usually 

 placed in the middle of the filament, though in some indivi- 

 duals it is situated nearer to the head. 



When the testes have been procured from an animal recently 

 killed, the vitreous humour, diluted with three parts of water 

 and filtered, is very appropriate for the observation of the 

 movements of the spermatozoids ; but this fluid is no longer 

 sufficient when the testes have been kept for one or several 

 days. In order, then, to revive the spermatozoids, we are 

 acquainted with nothing which succeeds better than solutions 

 of common carbonate or phosphate of soda, containing 5-lOOth 

 of the salt. By this means, even after the lapse of two days, 

 all the characteristic movements of the spermatozoids may 



