302 JORDAN. [Vol. VIII. 



substance, taking no visible part in the process of fertiliza- 

 tion. In all these respects the nucleoli resemble the infusorian 

 macronucleus. 



(i) It is universally admitted that cell nucleoli in general, 

 even if they do not arise directly from the chromatin network, 

 lie in the meshes of the chromatin coil and at their inception are 

 always in the most intimate association with it. Many good 

 observers insist that the nucleoli originate immediately from 

 the substance of the chromatin threads, but on this point the 

 evidence is still insufficient to produce conviction. 



(2) The general functional significance of nucleoli is still very 

 obscure, although many ingenious surmises on the matter have 

 been advanced. Strasburger and Pfitzner, as is well known, 

 regard the nucleolus as a place of storage of " reserve sub- 

 stance." On all sides there is a growing tendency to look at the 

 nucleoli as concerned either in the storage or the elaboration of 

 nutritive substance. In the amphibian o^gg, as we have seen, it 

 is difficult to avoid regarding the nucleoli in this light. In a 

 general way, also, it is true that the larger the Q^g, the larger 

 the quantity of nucleolar substance, seeming to point to a direct 

 ovogenetic relation. There is, on the whole, therefore, sub- 

 stantial reason for looking upon nucleoli, wherever found, as 

 concerned in one way or another with the active metabolism 

 (anabolism .?) of the cell. The fact that different types of 

 nucleolar-like bodies have been found by Carnoy and others 

 does not militate against this view. Indeed, the behavior of the 

 "plasmasomes" described by Ogata ('83) which wander out into 

 the cell and there become the so-called "Nebenkerne," playing 

 an important part in the regeneration of the cell, confirms the 

 essential similarity in function between these and other nucleoli. 

 One may legitimately suppose that these bodies which behave 

 thus differently towards stains — whether "karyosomes," "plas- 

 masomes" or "hyalosomes" — are in different stages of 

 nucleolar development, or even that a fundamental nucleolar 

 substance has differentiated according to the metabolic needs 

 of the cell and has assumed various allotropic forms. One 

 is not constrained to regard these bodies as fundamentally 

 unlike ; the presumption may be rather the other way when we 



