322 SCIENCE PROGRESS 



the authors have borne in mind the difficulties experienced in providing 

 compHcated apparatus for large elementary classes, and for this reason the 

 work will be of great use in all practical classes in agricultural chemistry, as 

 the possession of unusual apparatus or apparatus difficult to obtain is never 

 assumed. W. S. 



PHYSIOLOGT 



Physiology of Farm Animals. By T. B. Wood, C.B.E.. M.A., F.R.S.. and 

 F. H. A. Marshall, Sc.D. Part i : General, by F. H. A. Marshall, 

 Sc.D, [Pp. xii + 204, with 105 figures.] (Cambridge : at the 

 University Press, 1920. Price i6s. net.) 



The old story of the arising of science, from man's early efforts to master 

 the processes of nature, should make us give this book a hearty welcome 

 on the strength of its title, even if a welcome was not assured by the names 

 of the authors. The immediate and obvious benefits to be gained by the 

 practical application of a science bring in a driving force which assists 

 the progress of the general theory ; a gain for which the grounds of hope 

 are particularly good when the practical application is an extension of the 

 field, rather than an intensification of the study of some particular branch 

 which has long been put to a useful purpose. A survey of the work already 

 accomplished, and the fields where more work is most urgently required, 

 when presented to fresh minds, such a survey, we can say, may lead to no 

 small contribution to the science of Physiology. 



The first volume of the book before us, by Dr. Marshall, treats of the 

 general part of the physiology of domestic animals. It is to be followed 

 by a second volume on animal nutrition, by Prof. Wood. In the intro- 

 duction to the present volume, the author states that the physiology of 

 farm animals has been much neglected, a statement with which the agri- 

 culturalist would probably concur, since he would see that the author, in 

 the discussion of the elementary properties of protoplasm, has to resort to 

 inhabitants of the horse-pond more regularly than the horse. It would be 

 a dangerous experiment to ask a farmer if he was Hydra's keeper. Turning 

 to details, the first three-quarters of the book are pretty general, while 

 the last quarter deals with the generative organs. Of this latter portion 

 all we need say is that the author is Dr. Marshall, so praise would be super- 

 fluous, criticism dangerous. The earlier portion, however, requries closer 

 examination. The impression left on the mind, after reading the book, is 

 that the author has given far too much consideration to the man who wishes 

 to add two letters to his name for the minimum expenditure of effort. The 

 elements of the descriptive aspect of physiology receive the lion's share of 

 the space. This information is compact and well arranged, but the chapter 

 on Nerve would have been much improved by a short account of the sym- 

 pathetic system. The experimental branches of physiology have been 

 cut down very severely. The nerve muscle preparation receives very in- 

 adequate treatment. On p. 71, the dissociation curve of oxyhsemoglobin 

 is figured, but surely it would have been lawful to state that it was a 

 rectangular hyperbola — even to give its equation. 



The statement that the general form of the curve for carbon dioxide 

 in the blood is similar to that of oxygen puts a brutal strain on the word 

 "general," a strain which it ought not to be called upon to bear. The 

 selection of material is particularly difficult in physiology : no two men would 

 make the same choice ; but in the opinion of the reviewer the book would 

 have been improved if the subject had been treated as a growing and not 

 as a finished product. 



It is an excellent thing to get a number of pesple through the examina- 

 tion mill, the " practical application " of most textbooks, but if the gaps 



