M. Coste on the Formation of Cells. 97 



had assumed regular forms^ and in each vitelhne sphere had ac- 

 quired a generating activity which becomes a powerful cause of 

 multiphcation. 



There is then a distinct organic form, which may be considered 

 as a primary act of individualization, or a primary manifestation 

 of life, between the amorphous state of this matter and its actual 

 application to the formation of the cellular walls. This primary 

 act or this primary manifestation has for its object the forma- 

 tion of granular spheres, which, without being bounded by an 

 enveloping membrane, have already a true existence, are true 

 living individuals, inasmuch as they enjoy the faculty of repro- 

 duction, and in multiplying they become the active elements of 

 the organism, and contribute to the formation of the tissues of 

 which the organism is composed. 



For my own part, I am unacquainted with anything which is 

 more curious to observe than this progressive duplication of living 

 spheres reproducing in each secondary segment the reduced but 

 invariable image of the primary vitelline sphere. And in pro- 

 portion as we witness the realization of this remarkable phseno- 

 menon, we are as it were involuntarily led to seek, in the interior 

 of the substance which is doubled, some material arrangement 

 which may explain a metamorphosis, the cause of which cannot 

 be clearly found elsewhere. 



In fact, a more attentive examination soon shows that in the 

 centre of each vitelline sphere there exists a diaphanous homo- 

 geneous globule having a fatty aspect, and which cannot be com- 

 pared to anything better than a drop of oil. Seeing that this 

 globe appears in so constant a manner, we inquire if the division 

 of the vitellus cannot be attributed to its influence. But in order 

 to solve this problem, what passes in this same vitellus prior to 

 its division, and when it consequently appears as a simple sphere, 

 should be examined. 



We then see that the fatty or oleaginous globe, hidden in the 

 midst of the granulations of the primitive sphere, there undergoes 

 a contraction which divides it into two segments or distinct glo- 

 bules, and each of these segments seems to become a centre, which 

 tends to envelope itself in a portion of the surrounding granula- 

 tions, separating them from cells which are entangled by its fellow. 

 We should say, in short, that the vitelline sphere, excited simulta- 

 neously by two centres of action, yields to each of these centres 

 half the substance of which it is composed, and thus divides into 

 two segments which are immediately rendered spherical; each 

 segment of the vitelline sphere, being furnished with the oleagi- 

 nous globule which has excited the separation, then becomes in 

 its turn the seat of a similar process, and the division of its cen- 

 tral globule induces that of the secondary sphere which contains 



