94 



SCIENCE. 



[Vol. XIX. No. 471 



Those present in predominiting number are probably not the en- 

 tire cells, but are described as such for the sake of brevity. They 

 present the appearance of sharply stained nuclei, with scanty, 

 often indistinct, even apparently absent, cell bodies, and in favor- 

 able places their fibre-like processes can sometimes be traced a short 

 distance from the cell bodies. These bodies often appear as round 

 cells, and they are spoken of as such in this article, but they have 

 a more complicated structure than this designation would imply. 

 The next most important cells are larger than the round cells, but 

 their nuclei are not larger than those of the round cells. These 

 cells are usually of a columnar or rod shape, but sometimes they 

 appear to be conical. The nuclei invariably occupy the broader 

 ends of the cells, and each cell presents opposite to the nucleus an 

 acute terminal process. Finally, from the extremity of the cells 

 can sometimes be seen a stalk-like prolongation which passes down 

 between the round cells and probably becomes united with them. 

 The disposition of the various cells of the tumor is important. 

 The columnar cells arrange themselves in the form of circles or 

 rosettes, and this is accomplished through the juxtaposition of the 

 sides of the cell bodies, the acute ends of the cells pointing towards 

 the centre of the circle, while the periphery is formed by the 

 broad ends of the cells containing the nuclei. The latter vary in 

 size, depending on the number of cells concerned in their forma- 

 tion, and where the acute ends of the cells are in opposition, and 

 just before their termination, a very fine, although distinct, mem- 

 branous ring is formed, and projecting beyond this ring the delicate 

 processes of the cells forming their acute ends may be observed. 

 The round cells above described surround the rosettes. These 

 tumor cells are in many ways identical in appearance with the 

 external nuclei and rod and cone layer of the retina, as the author 

 shows. 



" If morphologically it is impossible to distinguish between the 

 round cells of the tumor and the cells of the external nuclear layer 

 of the retina, so do we consider that in each of the numerous ro- 

 settes can be seen the rod and cone layer of the retina reproduced 

 in miniature. For it is possible to see in the membranous ring 

 the external limiting mem.brane of the retina, beyond it, project- 

 ing into the lumen of the rosettes, the delicate processes of proto- 

 plasm corresponding to the rods and cones, and opposite to these 

 the nuclei to which these processes are united And then sur- 

 rounding these nuclei, which form a part of the external nuclear 

 layer, as it were, are the numerous round cells which are indis- 

 tinguishable from the cells of the external nuclear layer. It is not 

 to be considered that in every rosette the matured rod and cone 

 layer of the retina is reproduced' While this is the case in some 

 of them, others show a structure suggesting the embryonic type. 

 Hence this tumor is regarded as one in which the two most external 

 layers of the retina have been reproduced." 



The second part of the paper is devoted to a discussion of appli- 

 cability of the term "glioma" and the suggestion of the name 

 " neuro-epithelioma," and then with a consideration of the ques- 

 tion of the embryonic origin of tumors in general. 



A SEEDLING- BLACKBERRY PLANT. 



When poor little '" Jo" of Bleakbouse was told to " move 

 on," he did not appreciate the fact that everything in nature 

 is impelled by irresistable forces to " move on " to a higher 

 plane of existence, or suffer the only alternative, extinction. 

 Plants and animals must be able to respond to changed con- 

 ditions, must adapt themselves to their ever changing en- 

 vironment by various modiScations. 



Grant Allen has written some exceedingly interesting 

 chapters on the genealogy of certain plants. Nature seems 

 to have dropped a magic key into his hands, which admits 

 him directly into her presence, and he relates with charming 

 grace what she imparts to him. Although it requires a 

 skilled expert to "Dissect a Daisy," any one who will, may 

 read the fascinating story of evolution which is written on 

 the leaves of many plants. 



Now, here is a little seedling blackberry plant, which we 

 will take for our text. You will notice at the merest glance 

 that the leaves are quite dissimilar. The one nearest the 

 base being simply a plain, ovate leaf, with an irregularly 

 serrated margin. I wish you to notice particularly a certain 

 peculiarity in the venation of this leaf, viz., that the first 

 pair of veins near its base are quite prominent; that, leading 

 from these veins on the lower side, are also well-marked 

 veins; while on the upper side there are none, or very incon- 

 spicuous ones. There does not seem to be anything striking 

 or of especial interest in these facts, but, like the " magic 

 pear," which the artist, with a few strokes, converts into a 

 face, this peculiarity becomes gradually emphasized, until 

 later on in the series it may be called a characteristic. 



The second leaf differs somewhat from the first one, the 

 outline is more irregular. If, however, we read just a little 

 between the lines, we will see that it really has taken quite 

 a stride in advance; a little more careful examination will 

 reveal, what perhaps escaped our notice at first, that the' 

 difference between these two leaves does not consist wholly 

 in difference of outline. Again, it will be observed, the 



SEEDLING BLACKBERRY 



pair of veins near the base of the leaf are prominent, the 

 smaller veins leading from them being also well marked, on 

 the lower side only. 



With a little imagination, we can perceive that Nature is 

 busy at work with this '"magic leaf," and has already con- 

 ceived the idea of evolving from it the trifoliate leaf. With 

 this idea in mind, we can readily understand the significance 

 of the prominent veins, to which your attention has already 

 been called. We may consider them the frame-work of the 

 undeveloped leaflets. A notch is quite plainly seen on each 

 side of this second leaf, which nature evidently wishes to 

 continue and deepen until a new leaflet is given off on either 

 side. As if to render this lesult more easily accomplished, 

 she has omitted the frame-work in the portion of the leaf 

 where division is to take place. As proof that our imagina- 

 tion has not led us astray in our prediction as to nature's 

 plan, we have leaf No. 3 of our seedling. This leaf has 

 actually given off a leaflet on one side, and is evidently hus- 

 banding its forces for the elaboration of another on the oppo- 

 site side, the outline of which is already suggested by the 

 characteristic venatiou on the lower or outer portion. We 

 may almost say that half the leaflet is even now evolved. 



