August 29, 1889] 



NATURE 



419 



THL JOURNAL OF MORPHOLOGY— A 

 RECORD OF PROGRESS. 



"\1 7E have before us the third and concluding part of the 

 '' * second volume of this excellent publication. It 

 contains five papers (260 pages) with seventeen plates (with 

 one exception folding ones) and fifty-four woodcuts. The 

 illustrations are most admirable, and the plates, which 

 bear the magic names of Werner and Winter, possess an 

 exceptional charm. While all familiar with this Journal 

 must admit that it has, from the first, taken high rank 

 among its contemporaries, few will have been prepared 

 for the magnificent display of the part now under review. 

 With respect to its get up, the editors may well-nigh 

 defy competition, so liberally have the publishers re- 

 sponded to their demands. Much that is proffered is truly 

 American, in its revolutionary and highly sensational 

 character ; but, contrary to that which so often prevails, 

 the startling deduction is based upon a solid foundation 

 of fact, whereby the thing becomes tolerable, and the 

 reader's attention is arrested. A refreshing thoroughness 

 permeates the whole, and the work teems with originality. 

 The senior editor and Dr. W. Patten each contribute a 

 short paper embodying " facts and conclusions .... 

 stated in advance," of papers to be published in full in 

 forthcoming numbers of the Journal. It is in connec- 

 tion with these that the revolutionary element to which 

 we have alluded is most marked ; and the reader is 

 worked into a tremor of enthusiasm by the following 

 among other declarations : — 



" The eyes (of certain leeches) are segmental in origin, and 

 strictly homologous with the segmental sense organ-. . . . The 

 only evidence of an eye is a single la.-ge visual cell, oneithersideof 

 the head, without a trace of pigment investment. In view of 

 these facts . . . . we can no longer regard pigment as an 

 essential element of the leech eye. It will not d > to fall back on 

 the hypothesis of degeneration ; .... the visual cells are here 

 as perfectly developed as in the pigmented eyes, and the same is 

 true of the optic nerves. " 



Again — 



" The segmental sense-organs of tha leech are identical with the 

 lateral line organs of vertebrates," and " when we find strong 

 grounds for thinking that the lateral line organs have served as 

 the point of departure for the formation of gustatory, olfactory, 

 and auditory organs, our suspicion in regard to the eyes no 

 longer appears incredible.^ 



The paper in which the above cited statements occur is 

 entitled " Some New Facts about the Hirudinea," and 

 the author defines these animals as "a group, character- 

 ized by the possession of se^meftial sense-organs on the 

 first ring of every somite." Writing of the leeches in 

 especial relation to the progressive development of sense- 

 organs, he tells us that " nowhere is the transition from 

 lower to higher sense-organs so perfectly illustrated as in 

 the leech," and he then gives us the following remarkable 

 passage : — 



" Branchelliopsis, Clepsine, and Hiticdo reveal all the inter- 

 mediate steps, beginning with the purely tactile organ ; then 

 advancing to the compound organ, in which a l&y^ of the cells 

 have been modified to serve the purpose of vision, while the rest 

 have retained their primitive character ; and finally, culminating 

 after a long series of progressive encroachments — the visual 

 elements increasing gradually at the expense of the tactile — in 

 an organ in which the oiiginal function has been entirely 

 suppressed and a new one substituted for it." 



Again, we read — 



"As the metameiic arrangement of these sense-organs 

 characterizes marine as well as fresh-water and land leeches, and 

 as they everywhere agree in certain remarkable details of 

 number, topography, and structure, I am led to believe that the 



' Somevyhat similar views have already been postulated, for the eye by 

 Hill (Brnin, i888, p. 422), and for the taste organs by B2ard (Anat, Anz. 

 t888, p. 879.) 



diffuse or non-metameric arrangement, exemplified in Nephelis 

 and some other forms, has been secondarily acquired." 



Dr. Patten's " vorldufige^' is entitled "Segmental Sense- 

 organs of Arthropods." His concluding remarks read as 

 follows : — 



" The ventral cord and brain of Arthropods is at first composed 

 entirely of minute sense-organs, which in .Scorpions have the 

 same structure as the segmental ones at the base of the legs. On 

 the lateral edge of each ganglion of the ventral cord of scorpions 

 are two of these sense-crgans, conspicuous on account of their 

 size and dark colour. lo each segment of the brain are similar 

 but still larger ones. All these sense-organs are converted into 

 the ganglion- cells of the brain and ventral cord." 



The deductions above cited involve absorbing topics of 

 contemporary research. We eagerly await the full papers 

 and the discussions which they will raise, in the earnest 

 hope (on a knowledge of that which has gone before) of 

 an amicable settlement. 



Prof. A. E. Dolbear contributes a paper on " The 

 Organization of Atoms and Molecules," in reply to the 

 senior editor's renarks upon " The Seat of Formative and 

 Regenerative Energy," previously noticed in these pages. 

 The author deals only incidentally with the biological 

 aspects of the question ; he claims that 



"in late years chemists have adopted the term Chemism in 

 place of chemical affinity, and have given to it a greater range 

 of proclivities, finding no difference but one of degree between it 

 and cohesion ;" 



that 



"chemists have not attempted to give a physical explanation of 

 the cohesion of atoms into molecules, but have stopped with 

 chemism, as if it were an ultimate fact or property ; " 



while he attempts, as his chief object, to give 



"a physical explanation of chemism or atomic cohesion, and to 

 extend it to the building up of geometrical crystalline forms." 



To this paper the editor adds some trite remarks, for 

 which, in his modesty, he asks the reader's forbearance. 

 The editor claims that the article in question " cannot 

 be said to come strictly within the scope" of his journal. 

 With that we cannot agree. The physicist's view of the 

 nature of organic phenomena is very welcome, and we 

 are of opinion that much good would result could we 

 replace many a purely discursive biological article with one 

 such as this, if only with a view to a more definite agree- 

 ment with the physicist than at present exists, upon a 

 sound ba-sis for future work. 



The papers which will attract most attention are those 

 of Minot and Allis, upon the mammalian placenta, and the 

 lateral line systein in Amia, respectively. Each is a 

 masterly monograph : the chief interest of the first-named 

 centres in its revolutionary character ; that of the last- 

 named in its solidity and thoroughness. Prof. Minot 

 deals in full only with man and the rabbit, and he pro- 

 ceeds at the outset to supplement previous work in 

 matters of detail. He seeks to show that " the changes 

 in the uterus during gestation " are " a prolonged and 

 modified menstrual cycle," and that "the ovum has no 

 power of initiating the development of a decidna, but only 

 of modifying the menstrual process ; hence pregnancy can 

 begin only at a menstrual period." In discussing the 

 views of others he is dogmatical but never disrespectful, 

 and the following may well be cited in example : — 



"We know positively scarcely more than that the maternal 

 and fatal circulations are brought very close together in the 

 placenta. We infer that there must be a transfer of nutritive 

 material from one blood to the other. As to ivhat material is 

 transferred and hmv, we have only theories, but of them an 

 abundance. Ur.der these circumstances, the best beginning is 

 undoubtedly a frank acknowledgment of our ignorance." 



