MUSEUM 01' COMPARATIVE ZOOLOGY. 265 



coagulation, to artificial and post-mortem influences, or are present as struc- 

 tural features of living nuclei, Flemming offers the following reasons for regard- 

 ing the former supposition as improbable : — 



1. The regular form and arrangement of the network, which varies, it is 

 true, with the use of different reagents, but within very narrow limits. 



2. The constancy with which the nucleoli are found in the fibres (Balken) 

 of the network. 



3. The differentiations shown by the aniline staining to exist in the substance 

 of the network, which would be homogeneous were the network only a result 

 of coagulation. 



" The network," Flemming therefore concludes, " is the expression of a given 

 structural condition of the nucleus." 



Although finding the network very distinct in fresh sections of hyaline carti- 

 lage from the salamander, and thus being able to confirm Heitzmann's discov- 

 ery of the nuclear network in the cartilage of higher vertebrates, our author is 

 unable to convince himself, from the study of epithelial cells, that the extra- 

 and the intra-nuclear network are continuous, but states, on the contrary, that 

 the network of the plasma and that of the nucleus deport themselves quite 

 differently under the influence of the same chemical reagents. Flemming takes 

 exception to some points in R. Hertwig's conception of the nucleus. He be- 

 lieves his present paper is suflicient proof that the intranuclear network is not 

 limited to highly differentiated cells; and neither indorses its supposed nutri- 

 tive function nor is able to find evidence that it comes from the protoplasm 

 of the cell, — the less able since he finds no trace of pores in the nuclear 

 membrane. 



According to Lavuowsky ('76, p. 525, Taf. XXXV. Fig. 19. 1, 2, and 3), the 

 ganglionic elements of the ganglion spirale often exhibit about the nucleolus 

 the circle of granules described by Eimer. 



Arndt ('76), the substance of whose paper I know only through Schwalbe's 

 abstract in Hofmann u. Schwalbe's Jahresbericht, etc. (Bd. V., Anat., p. 25), 

 considers the cell nucleus as composed of a homogeneous semi-solid " Grund- 

 substanz " and imbedded " Elementarkiigelchen," each of the latter consisting 

 of a capsule and a contained dark corpuscle. The " Grundsubstanz " is ar- 

 ranged throughout in the form of a network in whose interstices the " Ele- 

 mentarkiigelchen " lie. 



In the human decidua serotina examined in warm, fresh serum, one finds, 

 according to Langhans ('76), that the nuclei are without trace of nucleoli or 

 granules, — homogeneous, lustrous, and with even outline. With the use of 

 reagents there promptly occurs (and in any event after the lapse of some time) 

 a separation of its substance — either throughout the whole nucleus at once, or 

 else beginning first at the periphery — into a highly refracting and a feebly re- 

 fracting portion. The latter collects into numerous small, round, closely packed 

 vacuoles. The former, the " septa," are at first of uniform thickness and very 

 delicate. The vacuoles become larger and the septa break through at first near 

 the periphery. Finally the whole nuclear substance (" Kernsubstanz ") is 



