April 1892.] THE BOTAXICAL SOCIETY OF EDINBURGH. 395 



nearest the yolk, and that in the nuclei the nucleoli are 

 lying in the direction of the source of food-supply. 



Facts 2 and o point out evidently that the nucleus and 

 nucleolus are concerned in the assimilation of food-material. 

 They may, indeed, only owe their partial stainability to the 

 fact that they serve as store-houses of highly elaborated 

 albuminoid materials, materials which will be converted into 

 the still higher achromatic elements of the cell. This sug- 

 gestion seems to be highly probable if one takes Hofer's 

 experiments into account, which showed distinctly that 

 albuminoid materials, taken up by an amoeba, the more they 

 are elaborated, i.e., digested, the deeper they are stained 

 by a dilute bismarck-brown solution. These observations, 

 conducted by staining amoebae, or rather their food- 

 supply int7'a vitam, are of the very highest physiological 

 importance. 



(4-) 111 following out the history of the parasitic embryo- 

 sac, we found that all the cells in the mature sac, with 

 exception of the three antipodal cells, show a feeble develop- 

 ment of the nuclear chromatin, the nucleolar and the 

 achromatic element predominating evidently. This may, 

 perhaps, have its reason in the antipodal cells being to a less 

 degree parasitic than their sister-cells, as they lie next the 

 plerome, and receive probably less elaborated nourishment 

 through this channel than the synergidoe, ovum, and endo- 

 sperm-cell, which, for their supply of nourishment, depend on 

 the death of the nucellar cells surroundins; the sac. 



If my view be correct, then what I have stated under 

 fact 3, in conjunction with Hofer's experiments, would show 

 the nuclear chromatin to be a less highly elaborated and less 

 assimilative albuminoid material than the nucleolar chromatin. 



(6) On the assumption just stated, we could explain also 

 why we find in the parasitic cells of the embryo-sac, at the 

 time of maturation, portions of nucleolar matter detaching 

 themselves from the main nucleolus to undergo a peculiar 

 gelatinous change. The gelatinous change would correspond 

 to a conversion of the assimilative material into achromatic 

 elements, an explanation which would also explain the dis- 

 appearance of nucleoli during the division of a cell. The 

 fragmentation of the nucleoli, on the other hand, would 

 correspond to a division of the achromatic element of the 



