DR. M. J. SCHLEIDEN ON PIiyTOGENESIS. 29/ 



morpha. Of the cellular nuclei evident in the spores only few, 

 in general only fi-om 2 to 4, serve for the formation of the cells ; 

 the others are quickly enveloped in chlorophylle, and thus with- 

 drawn from the \'ital process. The transpai'ent liquid in Avhich 

 these cytoblasts float, passes through the other stages of the me- 

 tamorphosis into cellular membrane just at the boundary of this 

 latter, and so rapidly, that the excessively delicate young cells 

 are distinguishable by nothing else than a fine, in general more 

 or less uninterrupted circle of infinitely small, black granules, 

 and by a scarcely perceptible greater transparency of the con- 

 tents of the newly formed cells in comparison with that of the 

 primitive cell ; and, finally, under the most favourable circum- 

 stances by the place where the newly originated cells come in 

 contact, and when this juncture is still covered by the mem- 

 brane of the primitive cell. (PL XV., fig. 18—20.) In the Cryp- 

 togamia, and especially in water plants, this may perhaps be 

 general ; and probably Mohl's division of the cells of Confervas 

 might be thus exjjlained. 



If we consider, however, that there are undoubtedly many 

 plants, among which should probably be reckoned more espe- 

 cially the Fungi and Infusorial Algee, in which we are totally 

 unacquainted, as yet at least, with the cytoblast, on account of 

 its absolute minuteness and transparency ; if further we bear in 

 mind that the nucleus in the cell-germ, even in larger cytoblasts, 

 appears frequently immeasurably small, or even with the highest 

 magnifying power, still entirely escapes the eye ; and, lastly, if we 

 deduce from what has been previously stated, that nevertheless 

 this granule, which can no longer be rendered perceptible, pro- 

 bably affords in the proper medium a sufficient cause for the for- 

 mation of cytoblasts with which the whole formative process of 

 the cells originates ; then indeed we are forced to confess that 

 imagination here obtains ample space to explain in every case 

 the origin of infusorial vegetable forms even without the aid of a 

 deus ex machina (the generatio spontanea). But it is my inten- 

 tion to communicate only facts and their immediate conse- 

 quences, and not to dream ; and I will therefore rather add a few 

 more observations on the growth of the plant. 



What is to grow} is a question which every child quickly 

 answers in the expression, " When I am as big as father." There 

 is truth in this answer, but this little will not satisfy science. 

 AN ords have no value of themselves, but are like coin, only signs 



