480 Miscellaneous. 



granulations which they contain not coloured blue, but the paleness 

 of the nuclear cavity contrasts strongly with the violaceous ground 

 of the protoplasm, which, in this stage, seems to be impregnated in 

 a diffuse fashion at once Avith the methylene blue and the eosin. 



The division-spindles, of which the centrosomes alone have some- 

 what more colour, contain neither granules nor chromatic fibrils. 

 It is necessary to examine at the end of the first day blastoderms 

 with from ten to twelve rows of cells, in order to find, in certain cases 

 of karyokinesis, a few extremely minato blue granules, which con- 

 stitute the first equatorial plate. It is, moreover, at this stage that 

 the protoplasm commences to exhibit the interesting peculiarities 

 upon which we shall proceed to dwell. 



From the thirty-sixth hour the methylene blue constantly reacts 

 in the manner which we have indicated above. 



Our double coloration therefore renders clearly evident the fact 

 mentioned by MM. Henneguy and 8abatier, namely that the nuclei 

 of the earliest embryonic stages are difficult to stain ; but it has 

 enabled us besides to recognize the appearance in the protoplasm of 

 the cells of elements to which we attribute great importance, be- 

 cause they seem to us to give the key to this peculiarity. Between 

 the twenty-fourth and the thirty-sixth hour, when only a few figures 

 of division exhibit affinity for the methylene blue, this stain sharply 

 distinguishes in the cellular protoplasm certain spherules, of which 

 the tint is so much the deeper in proportion as their dimeusions are 

 reduced. With objectives of high power we perceive that the largest 

 spherules diff'erentiate in the interior of their paler mass smaller 

 grannies of very deep colour, which are marked out within the sur- 

 rounding protoplasm. In neighbouring cells it may be observed 

 that these granules, whether isolated or arranged in a series, are 

 supported by the filaments of an aster : it seems that the latter 

 serve to attract them, or, at least, to direct them towards the middle 

 of the spindle, in order to furnish the elements of the equatorial 

 plate. Henceforth all the cells in process of division will exhibit, 

 contrary to what was seen in the first karyokineses, equatorial 

 plates which are very distinct and of a vivid blue colour. 



We do not think that the existence of these chromophilous 

 granules, representing the earliest condition in which the chromatin 

 substance manifests itself in the cells, has been mentioned before. 

 In a memoir upon the development of bony fishes Miecz. von 

 Kovalevsky represents the protoplasm of the cells of the blastoderm 

 as containing granulations which may be compared with those 

 which we are describing, but which are designated by him vitelline 

 cjramdations ("granulations vitellines"). Owing to the fact that 

 "the investigations of this naturalist were conducted tipon other 

 material and by the aid of methods different from our own, it is 

 impossible for us to discuss the interpretation which he gives to 

 these elements. We would merely observe, and we insist upon this 

 fact, that in our better preparations, where the chromophilous 



