April, 1904. 



KNOWLEDGE .^ SCIENTIFIC NEWS. 



59 



points to the inevitabu .:: .usion that <a:: ^: 

 primarily due to an irritant poisonous substance, that 

 such substance is secreted, in a spot liable to disease, 

 e.g., in glandular tissue, and that the blood is unable to 

 carry off or neiitralise the deleterious matter. 



The problem of an ultimate cure for cancer would 

 seem, therefore, to lie in the chemist's sphere rather than 

 the surireon's, li:.. firstly, in the careful analysis of fresh 

 cancerous tissue, and the isolation of the irritant prin- 

 ciple; and, secondly, in thediscoxery of an antidote to be 

 injected into the system just as antitoxin is injected for 

 diphtheria, to assist the blood in its function of eliminating 

 the injurious substance. It is a suggestive fact that antago- 

 nistic drugs are known to the substances which Galeotti 

 used in creating the pathological nuclear divisions so 



A 



B 



II 



A, — Epithelial Cells of Salamander, showing (i.^ iin.symmetrical 

 nuclear division after treatment with 0*05 per cent, anti'pyrin solu- 

 tion; 'ii.) tripolar di\ision after treatment with o'5 percent, potassium 

 iodide solution. B. — Human Cancer Cells, showing; <i.i unsymmetrical, 

 and ii.) tripolar nuclear division. [Both after Galeotti 



similar to those of cancerous tissue, e.g., strychnine is 

 antagonistic not only to nicotine, but to chloral, to which 

 atropine also shows antagonism. 



The similarity between cancer-cells and reproductive 

 cells in containing only half the usual number of chromo- 

 somes compared to normal somatic cells, and the further 

 discovery that the nuclei of all the cells in the sexual 

 generation (prothallus) of a fern show this reduction, 

 would seem to indicate that the occurrence of cancer- 

 cells in the bodies of man and higher animals shows a 

 tendency to a reversion to the remote state of things 

 when every single cell of the reproductive generation 

 partook of this peculiarity of the reproductive cell. It 

 •would be interesting in this respect to ascertain whether 

 the cells of the sexual generation in lowly creatures of 

 the animal kingdom, such as liver-flukes, jelly-fish 

 (Aiirelta), and some Tunicates (Salpa), &c., which exhibit 

 an alternation of sexual and asexual generations, show 

 the same condition as the fern prothallus in the vegetable 

 kingdom. 



Rare Living Animals 

 in London. 



By P. L. ScL.\TER, F.R.S. 



I \ the annual reports of the Zoological Society of London 

 will always be found a section containing a list of the 

 species new to the collection exhibited during the pre- 

 ceding year, and though, as we all know, it is continually 

 becoming more difficult to find " something new " in any 

 class of objects, it will be seen, on reference to the 

 reports, that even in the most recent years the list of 

 novelties is by no means a short one. There are, in fact, 

 always a considerable numlier of recent additions to the 

 Zoological Society's living collection of mucli interest, 

 and well worthy of representation by the facile fingers of 

 the artist, which we believe to be a much more generally 

 effective way of bringing the points of their shape and 

 structure into notice than the cheaper and more fashion- 

 ,ible photographs of the present day. 



It is with great pleasure, therefore, thai 1 ha\e under- 

 taken to write a few remarks on some of the rare and 

 interesting animals in the Regent's Park that have lately 

 formed the subjects of Mr. Goodchild's skilful pencil. 



1. The Thylacine. 



(Thylaciniis cyiwirphaliis. ) 



In the late Sir William Flower's excellent " Introduc- 

 tion to the Study of Mammals " the threefold division of 

 that order, originally proposed by Blainville, into " Or- 

 nithodelphia," " Didelphia," and " Monodelphia" is fully 

 maintained, although, for good reasons, Huxley's change 

 of these names into " Prototheria," " Metatheria," and 

 " Eutheria " is adopted, as being " far less open to objec- 

 tion." The Metatheria, as Flower points out, are repre- 

 sented in the present epoch by numerous species which 

 offer considerable dixersities in appearance, in structure 

 and in habits, although they all agree in many anatomical 

 and physiological characters which gi\e them an in- 

 termediate position between the Prototheria and the 

 Eutheria. The most important of the latter set of 

 characters is that the young of the Metatheria are brought 

 forth in a rudimentary condition, and are nourished by 

 milk injected into their mouths from the maternal 

 mamma;, to which they are firmly attached for some time 

 after their birth. During this process the young, in 

 nearly all cases, are sheltered in an abdominal pouch or 

 marsupium, whence the Metatheria have received the 

 more familiar name of " Marsupials." 



The Marsupials then, as we will call them, are usually 

 divided into two sections, the Diprotodonts and the Poly- 

 protodonts. Of the former of these, which with a few 

 unimportant exceptions are vegetable feeders, the best 

 known are the kangaroos of Australia and the adjacent 

 islands, while of the Polyprotodonts, which are carnivo- 

 rous and insectivorous, the finest and largest representa- 

 tive now living on the earth's surface is the Thylacine of 

 Tasmania, the animal represented in the accompanying 

 drawing. 



On first seeing the Thylacine alive the uninformed 

 spectator would naturally take it for a dog or a wolf. 

 And indeed in general external appearance the Thylacine 

 is excessively like one of these animals, but it is, never- 

 theless, undoubtedly a Marsupial in every essential part 

 of its structure, and like most other members of th«5 



