THE SEMEN. 185 



Structure. 



When first the spermatozoa were discovered and their 

 lively motions observed, much reluctance was entertained to 

 regard them as independent animals or beings ; and upon 

 this point, even amongst modern physiologists, there is still 

 an absence of accord, some of them attempting to explain 

 the movements exhibited on purely physical principles. 



Not many years ago a celebrated and talented continental 

 observer thus expressed himself in terms more ingenious than 

 accurate in reference to the nature of the spermatozoa : 



" When we place upon the object-glass of the microscope the 

 semen of a subject who enjoys all the energy of his generative 

 faculty, we there see corpuscles more or less rounded or oval, 

 having a sort of caudiform appendix : some have made animal- 

 cules of these little bodies, since they have seen that they 

 move, and have believed to have recognised in their move- 

 ments a determined direction, a character which they thought 

 could only appertain to animated beings. And as amongst 

 the microscopic animalcules which they knew there are those 

 which are provided with a tail more or less prolonged and 

 more or less dilated, they have assimilated to them the little 

 animalcules of the semen, and have made them Cercaria. 



" But you are about to see that the conformation and the 

 movements of the corpuscles in question may be explained 

 naturally, without our being obliged to have recourse to 

 the hypothesis of which I have spoken. It is certain that 

 we find in the sperm little gelatiniform masses more or less 

 rounded, oval, and having one part prolonged into the form 

 of a tail, like, in a word, to the drawings which Buffon 

 and many other observers have given us of the pretended 

 spermatic animalcules. These little masses float in a material 

 less consistent than themselves, and even fluid. But at first 

 their oval form results evidently from the manner in which 

 they reflect the light, and afterwards as the fluid in which f hey 

 are suspended a fluid which is itself more or less viscous 

 attaches itself strongly to them, it results that in the mi- 

 crosco-chemical movements which take place in the sperm, 



Q 



