REVIEWS. 



CHEMISTRY. 



Modern Inorganic Chemistry. — By J. W. Mellor, D.Sc. 

 871 pages. 316 illustrations. 8*-in. X 5i-in. 



(Longmans, Green & Co. Price 7/6.) 



No one who has had any experience in teaching chemistry 

 can fail to have been struck with the difficulty of inducing a 

 beginner to get a grasp of the general principles of the science 

 as distinguished from the numberless facts upon which they 

 are based. This is often lost sight of, however, in text books, 

 largely because a knowledge of detail "pays" best in examina- 

 tions. It is, therefore, a pleasure to meet with a book in 

 which stress is laid upon the point that it is more important 

 to train the reasoning faculty than the memory. In fact, the 

 views of the author on this point may be summarised in the 

 aphorisms that we find in different parts of his book ; as, for 

 example, " The best chemist is not necessarily he who is 

 familiar with the greatest number of compounds ; " and " Dic- 

 tionaries of chemistry, not the memory, are the natural store- 

 house of isolated facts." 



At the same time, it must not be inferred that the facts 

 essential to understanding a theory are omitted. On the con- 

 trary, throughout the book the evidence for and against 

 particular views is cited, and the student is, to a large extent, 

 encouraged to draw his own conclusions. The only instance 

 where generalisation seems to have been carried too far is in 

 the account of the elements of the rare earths, to which only 

 two pages are given. 



The chapter upon radioactivity is particularly clear and 

 full, and is well illustrated by diagrams. Although the author 

 does not expressly say so, he evidently regards the experiments 

 of Sir William Ramsay upon the transmutation of copper into 

 lithium and sodium as " not proven." Prominence is also 

 given in this connection to the view of Professor Armstrong 

 (1912) that "radioactive elements" may not be really elements 

 at all, but compounds of ordinary elements with helium. 



The book is quite sufficiently advanced to deserve references 

 to the original authorities, so that any student may be 

 encouraged to follow up a subject further. This would add 

 greatly to the value of the work. 



In an epilogue, Dr. Mellor remarks : " The teacher has 

 failed in his work if he has not whetted the student's appetite 

 for more." If we apply this standard to his own book we can 

 say without hesitation that no one with any taste for chemistry 

 can read it without being interested and stimulated both by 

 the matter itself and the way in which it is presented, with 

 appropriate quotations from great chemists and natural 

 philosophers as introductions to the different sections. 



C. A. M. 



Questioned Documents. — By Albert S. Osboun. 501 



pages. 200 illustrations. 10-in.X7-in. 



(London Agents for American Publishers: Sweet & Maxwell. 



Price 30/- net.) 



This book belongs to a class of works against which 

 objections are sometimes brought upon the grounds that they 

 may be of use to criminals and so defeat their own end. 

 But we venture to think that no one who studies Mr. Osborn's 

 most valuable book will endorse this view, for it will be seen 

 that the pitfalls are so numerous that in avoiding one a forger 

 must inevitably fall into another. 



Every scientific question which has to be answered in 

 deciding whether a document is genuine or not is here fully 

 discussed, and the author rightly lays stress upon the point 

 that a reason ought to underlie every expression of opinion 

 upon a matter of this kind. 



The methods used in the examination of the writing, the 

 paper, the ink, and so on, are described at length, and well 

 illustrated with diagrams and photographs of exhibits in actual 

 cases in which Mr. Osborn has been engaged. 



Throughout the book the use of scientific appliances is 

 advocated wherever practicable. Special cameras and 

 microscopes are described and directions are given for the 

 most suitable methods of applying them to the examination 

 of documents; micrometer callipers and micrometer eyepieces 

 are to be used for the measurement of lines and spaces ; and 

 the tintometer for recording differences in colour. 



In dealing with the judgment of handwriting the author 

 gives an excellent survey of the more modern and scientific 

 methods of solving a very difficult problem, while a separate 

 chapter is devoted to the effect of the position of the pen, and 

 the pressure applied to it, upon the character of the writing. 



There is only one important direction in which we can 

 suggest an improvement for a future edition. A short outline 

 of each of the illustrative cases so frequently cited in the text 

 might with advantage be added in the form of an appendix, 

 as is done in Mr. Justice Wills' " Circumstantial Evidence." 

 This would add greatly to the interest of the work without in 

 any way detracting from its scientific value. 



But even in its present form the general reader will find 

 much to entertain him in this book, while to the lawyer it 

 should prove invaluable. It has already met with a warm 

 welcome in America, and it only requires to become known to 

 be equally in demand in this country. r 4 m 



The Problem of the Gas-Works Pitch Industries and 



Cancer.— By H. C. Ross, M.R.C.S., L.R.C.P., J. W. Cropper, 



M.B., M.Sc, and W. J. A. Butterfield, M.A., F.I.C. 



48 pages. 2 illustrations. 8i-in. X 5-2-in. 



(John Murray. Price 6d. net.) 



For some years past the prevalence of warts, ulcers, and 

 epitheliomatous cancer among persons engaged in the distilla- 

 tion of gas-works tar and and the manufacture of briquettes 

 from gas-works pitch has been recognised, but hitherto no 

 explanation has been given of the remarkable fact that the 

 similar pitch from blast-furnace tar does not produce these 

 effects. 



In this little book we have the interesting results of a 

 research made by two physiologists and a chemist in an 

 attempt to discover the causes of this phenomenon. Starting 

 from the hypothesis that cancer is the result of certain factors 

 which include (1) rapid proliferation of cells upon a chronically 

 injured site ; and (2) an abnormal tendency of these cells to 

 migrate into neighbouring tissue, experiments were made to 

 discover what chemical agents were capable of stimulating 

 these tendencies to rapid growth and abnormal migration. 



The method employed was based upon the fact discovered 

 in 1909 by Drs. Ross and Cropper that human white blood 

 cells could be made to reproduce by cellular division, in 

 response to the action of certain chemical substances such as 

 creatinine, methylamine, and other compounds (extracted, e.g., 

 from dead animal matter). Some thirty-one different sub- 

 stances were discovered, capable of causing such cell prolifera- 

 tion, and to these the name of auxetics was given. The 

 action of these compounds was also proved physiologically ; 

 for, when applied to the surface of ulcers, they produced 

 granulation tissue and accelerated the healing process. 



A second class of bodies, working in association with auxetic 

 agents, caused unsymmetrical division of the blood cells and 

 excited amoeboid movements which would give rise to infil- 

 tration of the cells into neighbouring tissue. These bodies 

 were termed kinetics. Now, in experiments with aqueous 

 extracts of the two kinds of pitch, it was found that that 

 derived from the gas-works contained both auxetics and 

 kinetics, but that the extract from blast-furnace pitch, while 

 containing a small amount of auxetics, showed no signs of 

 kinetics, and did not produce amoeboid movements in the white 

 blood cells. 



190 



