67 



the divisions. The same phsenomena occur in the develop- 

 ment of the cells during the growth of the conferval fila- 

 ment and of other cryptogamic plants. 



fertilizing principle to the germ-cell, rather than to its essential ope- 

 rations when arrived there. 



The best microscopical examinations of the spermatozoa show "that 

 the spermatozoa are everywhere void of a special organization, and 

 consist of an uniform homogeneous substance which exhibits a yellow 

 amber-like glitter." Art. SEMEN, Cyclop, of Anatomy, vol. iv. p. 502. 

 The nucleus of the Polygastrian offers the closest resemblance to this 

 character of tissue. And perhaps it may not be out of place here to 

 notice the close analogy of the modification of form which the nucleus 

 of some of the larger Polygastria, Stentor Roeselii e. g., presents to the 

 spirally disposed elongated head of the spermatozoon in the Torpedo, 

 Pelobates, and the Passerine birds. 



The reception of the matter of the spermatozoon by the germ- cell is 

 the essential preliminary to the primary processes of its spontaneous 

 fissions : and when we see these fissions governed in the germ-cell of 

 the Ascaris by the act of impregnation, followed by the appearance of a 

 pellucid nucleus in the centre of the opake and altered germ-cell, and 

 when we further see its successive fissions governed by the preliminary 

 division of the pellucid centre, are we not naturally led to infer that that 

 centre is the seat or the chief seat of the spermatic principle which the 

 germ-cell has received ? The mind must either be a mere passive recipient 

 of these phenomena, or we must reason upon them and ask ourselves 

 their meaning. The most probable signification of the appearance of 

 the pellucid centre and of the initiative which it takes in the subsequent 

 changes may be that which I have just explained : but this is certain, 

 that the analogy between these phenomena in the multiplication of the 

 parts of the germ-mass and those of the nucleus in the multiplication 

 of the monads is so close, that one cannot reasonably suppose that the 

 nature and properties of the nucleus of the impregnated germ- cell and 

 that of the monad can be different. 



Therefore I infer that the nucleus of the Polygastric Animalcules is 

 the seat of the spermatic force: it can only be called 'testis' figura- 

 tively : it is the essence of the testis. It is the force which governs the 

 act of propagation by spontaneous fission : and if Ehrenberg be correct 

 in viewing the interstitial cell- corpuscles (kornchen) as germ-cells, 

 these essential parts of ova may receive the essential matter of the sperm 

 from the nucleus which is discharged along with them in the breaking 

 up of the monad, which Ehrenberg regards as equivalent to an act of 

 oviposition ; and impregnated germ-cells may thus be prepared to 

 diffuse through 'space and carry the species of Polygastric Animalcules 



