128 Proceedings of the Royal Physical Society. 
As the various “ organs” of a cell (vide Figs. 1, 2a, 2b), we 
may consider the endonucleolus, with its radiating tubes ; the 
nucleolus; the nuclear chromatin segments; the nuclear 
achromatic matter proper; the cytoplasm or plasm found in 
the body of the cell; the attractive sphere with its central 
body, also known as the archoplasm and the centrosome ; 
vacuoles; and, finally, leucites or plastids, e.g., secondary 
nuclei, chlorophyll corpuscles, ete. 
We are, as yet, far from understanding definitely what 
functions each of these various organs of a cell has to fulfil; 
still a sufficient number of facts has been established to 
enable us to say something definite regarding the functions 
of the nucleus. In a previous paper,! and also in the 
“Proceedings” of the Biological Section of the British 
Association, 1892, I have given a short summary of facts 
observed by other investigators and by myself, which have 
led me to the conclusion that the chromatin segments of 
the nucleus are organs consisting of an essential achromatic 
framework, in the interstices of which particles of food- 
material are being elaborated, and that the stainability of 
these segments depends on the presence of the nutritive 
matters in question. To put-it differently, the chromatic 
element of the nucleus, which is so highly esteemed by 
most histologists, and which Strasburger, de Vries, the two 
Hertwigs, Weismann, etc., consider to be the ideal heredi- 
tary substance, is nothing but a supply of food on its road 
towards conversion.into the various achromatic plasms, 
which latter form the essential bases of the different organs. 
The nucleolus I hold to be either an organ for the further 
transformation of “nuclear” chromatic food-substances, or 
simply a storehouse for material elaborated by the nucleus. 
My views are based on the following observations :-— 
(1) Both nuclei and nucleoli tend to occupy that part 
of the cell which is nearest to the supply of food, as readily 
demonstrated in the vegetable kingdom in the sporangia 
of Z'mesipteris, Selaginella, and all Angiosperms, etc., and 
as seen in the animal’kingdom in the ganglion cells of the 
1 Gustav Mann, The Embryo-sac of Myosurus—Trans. Bot. Soc. Edin., 
1892, pp. 351-428, . 
