296 M. E. Claparede on the Theory of the 



minal vesicle. When the ov.i become larger, the extremity of 

 the csecum opens and a small quantity of albumen passes out 

 from it ; this is to serve as a bait to the spermatozoids (! !). The 

 ovum then exactly resembles one of those glass flasks used in 

 chemical laboratories, furnished with a rather short neck. The 

 spermatozoids arrive from all sides, allow themselves to be taken 

 by the bait, and penetrate into the neck of the ovum, or the 

 micropyle, to employ a name now received in science. In its 

 frolics the spermatozoid loses its tail, so that only its oval head 

 is found in the neck of the ovum, and this usually occupies a 

 transverse position. It is difficult to describe the ecstasy in which 

 Keber was plunged at this discovery, on the day when he was 

 permitted to see " that which no mortal eye had yet contem- 

 plated." Overwhelmed with enthusiasm, and believing himself 

 initiated into the mysteries of creation, he concludes his first 

 chapter by exclaiming (in two languages) — ''And the evening and 

 the morning ivere the first day \" (Factumque est vespere et mane 

 dies unus ! Da ward aus Morgen und Abend der erstcTag !) ! ! ! 

 But this is not the whole ; — Keber follows the journey of his 

 s])ermatozoids into the eggs, where he is clever enough to recog- 

 nize them, sometimes by their form, sometimes by their greenish 

 tint, and sometimes because they begin to jump about (probably 

 they go into convulsions) under the influence of sulphate of 

 strychnine*. The spermatozoid has lost its tail, which greatly 

 facilitates research, seeing that if it was necessary to seek for it 

 in the egg, its delicacy would certainly prevent its being found. 

 But we may be allowed to ask how this spermatozoid is to be 

 distinguished from any other granules, for it is well known the 

 spermatozoids of the Anodontce are far from being of gigantic 

 stature. The idea of a blackish tint being characteristic scarcely 

 needs refutation. The imperfection of our best achromatic 

 glasses still communicates to certain objects a tinge which varies 

 according to the microscope, without taking into account the 

 phsenomena of diffraction, which must occur at the edges of 

 a small object situated in the interior of the egg. Henlef indeed 

 speaks of a yellowish tint in the human spermatozoids ; but he 

 takes care to add, " in a certain illumination." Besides, as the 

 old proverb says — De coluribus non est disputandum. However, 

 Keber pretends to recognize the spermatozoid with certainty and 

 pursues the investigation of its evolution. "Week by week he 

 describes the changes which it undergoes, until the moment 

 when it becomes decomposed into granules, which probably 



* It is however to be observed that it is precisely this agent that is era- 

 ployed, as well as chloroform and oil of bitter almonds, to dejmve the 

 spermatozoids of man and other animals of their mobility. 



t AUgemeine Anatomie, ]). \)\d. 



