500 



NA TURE 



( ). 



1923 



/Idtnin inflv hiilfv is iin!\crs;illv :i(< fptcd on lllC 



oiK'iiiiblu^ — vvliicli o 

 ixK anccd niiiv Ix- \ \* w 



lii .1; 

 liaiMii' 



The case is similar, aii^ 

 the characters coiiternt < 



! lit I : ;w;iii.i , : ' ' Hi, n l(rc(l 



,1 a rrlati\il\ ]>niniti\c 



.< I iall\ 111 1 111- ail i-iii «■ 



: !h meaning ol cithfr 

 I' rn. 

 (lied must be SO, Willi all 

 iiisiij( red as thrv arc hv 



the author on the broad lia>i, i.t ^tr-i' mral c"mi)arison 

 alone. It is so, for cxamiilc, m t ' n ol the 



vascular system of the axis. iIm \. n,.,,..,, ... the leal. 

 and the gametophytic generations ; lor aUhou<;h wr arc 

 now in possession of the fullest knowledge of the 

 distrihiiiion and structure of vascular tracts and of the 

 omanisaiion of the sexual generation of many ferns, we 

 still know nothing of the meaning of roiidu'ti\e tissue 

 in the ontogeny of any organism, or of the true values 

 to be assigned to the gametophytes of any fern whi( h 

 may figure in a systematic discussion. 



In the hands of a less skilful writer and pleader the 

 conceptions of '' biological ])rot)al)ility " which underlie 

 the author's treatment of structural characters might 

 seem less alluring than they do in the pages ot this 

 volume. The weakness of the morphological method 

 lies indeed in its inherent inability to explain the 

 characters considered. It must always be so, until 

 a closer co-operation has been secured and persistently 

 maintained between morphological and physiological 

 investigators. Its strength lies in the knowledge that 

 for long it must remain the sole avenue to wide general- 

 isations on phyletic relationships. To its weaknesses 

 and to the tentativeness of the conclusions secured by 

 morphological study alone, the author of this work is as 

 fully alive as is any student of phylogeny who would 

 arrive, at some distant period, by physiological inquiry 

 at a reasonable understanding ot anv life-process. 



The ver)^ doubts and fears which the consideration of 

 this book must naturally arouse for those who have not 

 employed the author's methods are, however, integral 

 parts of its purpose. We are on the eve of new departures 

 in morphological inquiry, in which a closer alliance 

 between the pure physiologist and the morphologist 

 will be secured. It is good, then, to have this treatise at 

 this time providing the sum of knowledge in a branch 

 of biological science so admirably condensed, and the 

 philosophy which has grown with it so skilfully and so 

 clearly presented. The day of the formal morphologist 

 is past : the day of the causal morphologist is already 

 with us. It may yet be possible to present a work in 

 which a chapter ori " the habit and habitat of ferns " 

 will form a satisfying conclusion to the treatise as a 

 whole, for these are the expressions of the sum of the 

 characters with which the author has dealt so ably. 



NO. 2814, VOL. I 12] 



Whatever will tte the fate of the rlassifiratinn whi( h 



t he second \ I ijiii: ■ .' ' 



volume will slana 



iic thotiL'ht anfl wor 

 uIjo Inr .! : ■ : biological 



ini|nii, , 1 i,' :. ' ; ims i>o(»k snoum im- read and 



re n h1 I r\M\ iiitni of descent, and its matter 

 will lie i!n(loiiliie(ll\- considered as a statement of 

 stru( tural l.ut wIik h lia.s seldom Ixren surpa.sscd in the 

 lit( ratun ol the natural sciences for clarity and just 

 ju(Liiient. J. McL. 'I"- 



Our Bookshelf. 



\ 



s. 65-71. 



I'; ic plates. 



Institution. \u22.) 3.50 



I'l 



Contyi}r.' 



(Publication \- -r, 

 (Washington ; (arm 

 dollars. 



Amonc. noteworthy pa'" '^ -'■ »'" <'■ 'lupment of the 

 circulatorv svstem b\ H. Woollard, 



Morem e R. Sabin, anu -iiri-. im.-, volume contains 

 an inii)orlanl ( untributioii by Charles A. Doan to the 

 solutmn ol the i)rol>lem ot tlie bone-marrow circulation. 

 1 lis method of iiuestigatioii u as general injection, under 

 a pressure of 130 mm. of mercun,', with an Indian-ink 

 solution, of the vascular system of about forty pigeons. 

 \\\ this means he ( laims to iia\e brought to light the 

 existence ol an exteiisixe ( ai)illary plexus connectmg the 

 branclus ot the sinusoidal. \ enous elements, arranged 

 in luits. which jtrobably form the active, functioning 

 vascular bed ut tlie bone-marrow. 



It is suiiuesled that the normal slate of iht.se blood- 

 channels, which must be studied in hypoplastic 

 marrows, is one of collapse. This view the author 

 correlates w ith his conclusion that the vascular system 

 of the bone-marrow is a ( losed system, and with 

 Drinker's discriminatim: statement that red cells are 

 apparently found outside the blood-stream, and enter 

 the moving current as a result of growth pressure, but 

 that their extravascular origin is not implied by this 

 presentation of the tacts. It is clear that the capillar}- 

 system described would add to the endothelium of the 

 larger vessels the amount represented in a close and 

 extensive network throughout the marrow. In the 

 liL;ht of this, Sabin's work •' '' Tigin of blood-cells 

 in tile chick emt>rvo is re\ : -he venous sinusoids 



of the author's text are tlie :-n:r-.s capillaries of most 

 other writers. There is much to recommend the new 

 term. Another j)oint of int ' " r~ 



description of the relation bet ■ 



marrow and those of the ]ierio>uum. ami <-; ihe com- 

 pact tissue of the diaphysis. 



Die Vegetation der Erde. Her. 



Engler und Prof. 0. Drude. ^ I'jlanzcnuctt 



der^bolivischen And en :ird /■ '-rn Vorlandes. 



Von Prof. Pr.Th.l! ';.. \ in -- - ^ - 



W. Engelmann. iQ-\; '; ^^o mcii-k- 

 The first part of the work under \v with the 



physical geography of Bolivia, a lounu; . omprising 

 both high Andean tableland and moist tropical forests. 

 This is^preceded by a short account of the various 



