366 Prof. E. Claparede on the Reproduction of the Aphides. 



under the microscope.'' Now is there anything characteristic in 

 the Amoehce except their mobility ? The mode of movement 

 alone distinguishes an amoeboid body from a drop of albu- 

 minous substance. Has not M. Balbiani, preoccupied by the 

 notion of finding zoospermia in the Aphides, recollected that in 

 some animals (certain Nematode worms^ for example) the sper- 

 matic elements have a form which has been designated as 

 amoeboid ? If this be the case, he has forgotten that the mode 

 of movement alone led to the application of such an epithet to 

 these zoospermia. 



Moreover I repeat that the asserted disappearance of the 

 green mass, upon which M. Balbiani lays so much stress in 

 order to give probability to its testicular function, does not 

 occur. The green cells persist, each retaining its nucleus and 

 pre&erving in its interior the spherical globules, the latter not 

 being transformed into either amoeboid or bacilliform elements. 

 This we may ascertain simultaneously from different generations 

 contained one within the other. This essential point may easily 

 be verified by any one ; and whoever will take the trouble will 

 find all doubt dispelled from his mind on this point. 



But how are we to explain M. Balbiani^s statement ? for in 

 this case we have to do not only with a question of interpreta- 

 tion, but also with a question of fact. I think that M. Balbiani 

 himself furnishes us with the means when he says that at the 

 first glance he thought he had to do with parasitic vegetable 

 organisms. This first impression was no doubt an inspiration in 

 the theological sense of the word. A. morbid state of the in- 

 dividuals investigated by M. Balbiani can alone account for the 

 essential differences which distinguish this part of his observa- 

 tions from normal phenomena. In connexion with this it is 

 not uninteresting to find that at Naples the Aphis of the Rose, 

 and especially its pseudovaria, are infested by parasitic Muce- 

 dinese. 



The function of a secondary vitellus ascribed by M. Meczni- 

 kow to the green mass is at all events more probable than that 

 of a testis. This organ may very well serve as a magazine of 

 assimilable substance when the primary vitellus is absorbed. 

 The analogies of the green mass to a vitellus, both in appear- 

 ance and position, are at any rate so great that Mr. Huxley 

 regarded it as a true vitellus. An objection to this view may 

 be derived from the fact that the organ in question exists not 

 only during the embryonic period, but also throughout life. 

 However, it must be remarked that its relative importance 

 diminishes gradually with age, and that consequently the ob- 

 jection loses much of its weight. 



To sum up, the theory of the hermaphroditism of the 



