TRANSACTIONS OF SECTION D. 753 



similar to those of peripheral g-anglia generally, except in that they possess no 

 special envelope lined by endothelial cells. It is worthy of note that the large 

 arteries of the organ exhibit a fine nerve plexus between their middle and internal 

 coats, similar to and directly continuous with that ordinarily described between the 

 middle and outer coats of larger blood-vessels generally. 



If the organ be examined in March, r>., towards the close of hibernation, many 

 of the cells will be seen to exhibit remarkable changes. 



These changes appear to start in the nuclei, which begin to swell, assume a 

 more completely spherical shape, lose some of their chromatin, and so reveal certain 

 changes in the nucleolus which can now be seen to contain one or more colourless 

 endo-nucleoli ; from this nucleolus there are given off from time to time para- 

 nucleoli, which pass gradually towards the periphery of the nucleus, meanwhile in- 

 creasing in size, and presently find their way through the nuclear membrane into the 

 surrounding protoplasm, where they break down and disappear; as the nucleus 

 becomes more and more devoid of chromatin more of these bodies are produced, 

 only one or two at a time, however, which, after piercing the wall, break down in 

 the protoplasm ; finally, the nucleolus itself passes towards the periphery of the 

 nucleus, applies itself to the nuclear membrane, causing it to bulge somewhat at one 

 point, through which it eventually passes into the surrounding protoplasm, to break 

 down there just as the para-nucleoli have already done. After the passage through 

 it of the nucleolus, the nuclear bag, still containing a few strands of chromatin, 

 collapses and finally also disappears. 



Whilst these changes are going on in the nucleus, the fat stored in the cell 

 is gradually absorbed, and eventually entirely disappears ; the cell wall disappears, 

 and the protoplasm also exhibits changes ; its network becomes less distinct, the finer 

 strands seeming to give way, producing a finely granular appearance throughout 

 the cell, amongst which a peculiar coagulable colloid-looking material may some- 

 times be seen which finds its way into the capillaries, and thence into the veins, 

 where it appears in hardened preparations as a uniform hyaline mass with the red 

 blood corpuscles imbedded in it. This material is not of the nature of glycogen, 

 but possibly rather allied to lecithin. Eventually the whole cell disappears. 



This change does not occur in all the cells simultaneously, but in groups of 

 cells here and there, giving rise in those places in which it has been going on for 

 some time to an appearance of greater vascularity, owing to the capillaries 

 formerly separated by large cells gradually coming together as the intervening 

 cell mass is absorbed. 



By this process the very voluminous body present at the commencement of 

 hibernation gradually dwindles away to almost nothing soon after the animal 

 awakes from its winter sleep. 



5. The Functions, Staining Beadions, and Structure of Nuclei. 

 By GusTAV Mann, M.B.G.M. 



The author holds the following views : — 



1. The nuclear chromatin segments are organs for the transformation of simple- 

 into more complex compounds. 



2. The nucleolus is a storehouse for material which has been elaborated by the 

 nuclear segments. 



These views are supported by the position of nuclei and nucleoli relatively to 

 their cell walls and the supply of food, as seen in the vegetable kingdom in the 

 sporangia of Tmesipteris, Selaginella, the embryo-sac of Angiosperms, &c. ; and as 

 readily demonstrated in the animal kingdom in the ganglion cells of the retina, 

 during the development of the chick, in the alimentary canal of the salamander, &c. 



3. The staining reactions of nuclei and nucleoli during their ' resting ' and 

 'asexual' condition, during division and senescence, and during the period of 

 * sexual ' differentiation may be represented thus : — 



1892. 3 C 



