14 



KNOWLEDGE. 



[November 1, 1880. 



wliieh both living and dead wood are attacked, probably to 

 a mucli larger extent than is generally imagined. The 

 subject is one so new to the English reader, and yet so 

 intrinsically important, and one withal which raises so 

 many interesting biological questions, that this masterly 

 exposition of it cannot fail to be welcomed as one of the 

 most valuable additions to recent popular scientific litera- 

 ture. The cluef facts connected with the microscopical 

 structure of the ditierent parts of a tree-trmik are dealt 

 with in two explanatory chapters (one on the wood, the 

 otlier on the cortex and bark) in so remarkably lucid a 

 manner that no one need plead the scantiness of liis 

 botanical Imowledge as an excuse for not reading the book. 

 The woodcuts are both numerous and excellent, and 

 several of them represent specimens fi-om the classical 

 series prepared by Prof. Hartig for t]ie iluseum of Forestry 

 at Mimich, an institution lately ^^sited by the author. A 

 long and rather difficult chapter has been added on the 

 j)erplexing question of the cause of the ascent of sap in 

 tall trees, and gives, for the first time in an English work, 

 an epitome of the various modern theories on the subject, 

 together with an accoimt of the progress of the contro- 

 versy during the last thirty years. As a good knowledge 

 of the fimdamental laws of physics is requisite for the 

 mastery of this chapter, it will probably present difficul- 

 ties to the general reader ; but, as it is quite complete in 

 itself, it may be passed over by those who desire to do so, 

 without detriment to the rest of the work. In connection 

 with the diseases of timber the main point emphasised by 

 the author is " the destructive action of mycelia of various 

 fungi, which, by means of their powers of pervading the 

 cells and vessels of the wood, and of secreting soluble fer- 

 ments which break down the structiu-e of the timber, 

 render the latter diseased and unfit for use." The chapter 

 on " dry rot " deserves the closest attention of all who 

 have any responsibility in connection with house property, 

 and the warning held out concerning the danger of 

 leaving the cut base of a branch on a growing tree ex- 

 posed to the attacks of micro-fungi, claims thoughtful 

 consideration on the part of all w^lio are mterested in 

 forestry. 



Haneij oh the ( iiaihition of the Blood. Edited by Alex. 

 Bowie, M.D. (George Bell & Sons.) — The depths of error 

 and misconception which existed at the commencement of 

 the seventeenth century as to the functions of the heart, 

 and fi-om which William Harvey did so much to rescue 

 medical science, together with the means by which he 

 arrived at his splendid generalisation, have hitherto been 

 known only to the few, and therefore the publishers of 

 " Bohn's Select Library " have done well to add this 

 volume to then series, thus rendering easily accessible to 

 the public the details of that great discovery. The reader 

 is here presented \nth a translation of Harvey's original 

 Latin treatise " On the IMotion of the Heart and Blood in 

 Animals," and of his two " Disquisitions on the Circula- 

 tion of the Blood," addressed to Riolau of Paris, in answer 

 to objections. The translation is a revision of Willis's 

 edition, published forty years ago under the auspices of 

 the Sydenham Society. To this Dr. Bowie has prefixed 

 an interesting biographical notice of the " simple, modest" 

 little professor, the announcement of whose discovery so 

 startled the world of his day that twenty years afterwards 

 he was able to exclaim, " Scarcely a day, scarcely an hour 

 has passed since the birthday of the Cu-culation of the 

 Blood that I have not heard something for good or for e\"il 

 said of this my discovery." At a time when the authority 

 of the ancients was stiU paramount, and " the divine 

 Galen " was venerated as an oracle, it needed no little 



hardihood to give to the world a book so revolutionary in 

 its ideas, and even the prestige of his position as Court 

 physician did not avail to protect the autlior from detrac- 

 tion, for he is himself reported to have said that, '• .\ftcr 

 his book came out, he fell mightUy in his practice ; 'twas 

 believed by the vulgar that he was cracklirained, and all 

 tlje physicians were against him." lielicving that the 

 intimate connection of the heart with tlie lun^s in the 

 human subject was one of the chief causes of the pre- 

 valent misconceptions of the functions of those organs, he 

 condennied strongly those anatomists who " confine their 

 researches to the human body alone, and that when it is 

 dead." He was thus led to pay great attention to com- 

 parative anatomy, expecting by the dissection of other 

 animals in which the organs are placed in difl'ercnt relative 

 positions to get at the truth, and this notwithstanding the 

 sneers of those " who derided the introduction of frogs and 

 serpents, flies, and others of the lower animals upon the 

 scene, as a piece of puerile levity." How fully he was 

 cou^•inced ot the supreme value of the experimental and 

 inductive method is evident throughout ; the most ad- 

 vanced scientist of the present day could not express him- 

 self more strongly than this : " I profess both to leai'U and 

 to teach anatomy, not fi'om books, but from dissections" ; 

 or again, " Our first duty is to inquire whether the thing 

 exists, before asking why it exists." By acting on such 

 principles he was able to demonstrate that the heart was 

 the great propeller of the blood instead of the " generator 

 of ^•ital spirits and of heat," and that the veins and 

 arteries were equally portions of the route taken by the 

 whole of the blood in its circular coiu'se through the body, 

 instead of being intended, the former to contain most of 

 the blood, and the latter only a little, and that mixed 

 with air and " \ital spirits." Enough has, it is hoped, 

 been said to show that this book contains much that is of 

 interest, not merely to the technologist, but to any and 

 every one who cares to inquire into the history of the 

 conquests of science. 



The Zoo. Second Series. By the Kev. •!. G. ^\'ooD. 

 (Society for Promoting Christian Knowledge.) — A capital 

 book for children. It is admirably an'anged with letter- 

 press and illustrations judiciously combined, so that every 

 page contains a picture, either plain or tinted. As these 

 are by Harrison t^eir, and many of them represent spirited 

 scenes in animal life, there is no chance of the yoimg 

 people's interest flagging. The present series illustrates 

 the W^easel family. Seals, Rodents, and Oxen, and the 

 descriptions, by the late Eev. .T. G. Wood, contain just the 

 sort of information chUdreu deUght in. 



Hou- to Teach Arithiiietir. By T. .J. Lr-esey. (Moffatt 

 & Paige.)— This little book consists of a series of notes of 

 elementary lessons on Arithmetic, from Numeration and 

 the use of the Abacus to Proportion and some of its more 

 important apphcations, intended to show the teacher how 

 to lead his pupils to a comprehension of the nitiomde of 

 the various "rules." The fact that it has reached its 

 ninth edition seems to indicate that it has been found 

 useful by many persons, chiefly, it may be presumed, 

 amongst the ranks of junior pupil teachers. The methods 

 advocated are sound, and if the book has a fault, it lies in 

 prolixity, and in the fact that so very little is left for tlie 

 intelligence of the teacher himself to supply. 



The liotif'era, or Wheel Aninitdeulcs. (Supplement.) 

 By C. T. Hudson, LL.D., F.R.S., assisted by P. H. 

 GossE, F.E.S. (Longmans, Green and Co.). — The present 

 issue forms the completion of a most laborious task. Dr. 

 Hudson's great work was originally intended to contain in 

 two volumes descriptions of the Rotifera of the whole 



