REVIEWS 347 



English work devoted entirely to this subject. In the opening chapters the early- 

 theories of chemical combination are passed in review with special reference to the 

 parts played by the doctrines of constant and variable valency. 



The importance of the periodic classification as a guide to valency may be 

 gauged by the fact that the author devotes twelve chapters to a consideration of 

 the habits of combination of the elements arranged in their natural families. The 

 evidence collected in support of the views expressed is generally accompanied by 

 references to the original papers. This bibliography will greatly enhance the 

 value of the book to the serious student, who will also read with appreciation the 

 author's exposition of Werner's theory of valency. 



Under the heading of electro-chemical theories the author deals with the deas 

 put forward from time to time regarding the nature of valen cy. The modern 

 electronic theories of valency are discussed, and the author elaborates his own 

 views, which afford an alternative explanation of the constitution of the metallic 

 ammines studied by Werner and others. 



The concluding chapter gives a brief outline of one or two of the most 

 important theories other than those based on electrical hypotheses. It is to be 

 regretted that Barlow and Pope's theory is not discussed in greater detail, inasmuch 

 as this conception, unlike all the others, is based on crystallographic considerations. 



The work may be recommended as a useful introduction to the present know- 

 ledge of the phenomenon of chemical valency. 



G. T. Morgan. 



Rational Immunisation in the Treatment of Pulmonary Tuberculosis and 

 other Diseases. By E. C. Hort, B.A., B.Sc, M.R.C.P. [Pp. 75.] 

 (London : John Bale, Sons, & Danielsson, Ltd., 1909. Price $s. 6d. net.) 



Under this title the author gives a sketch of natural recovery from bacterial 

 infections, and treatment by means of artificial inoculation, together with an 

 account of autolysis, enzymes and antienzymes, and cognate matters. He holds 

 that auto-inoculation involves inoculation against the products of tissue-change 

 present in bacterial lesions, and that this is neglected in vaccine therapy. 



He contends that the presence or absence of auto-inoculation and the presence 

 or absence of response are both indicated in temperature charts in febrile cases, 

 which are thus a reliable register of the progress of immunisation. Charts in 

 support of this view are reproduced, chiefly from cases of phthisis. 



Advantages are claimed for auto-inoculation over vaccine therapy, the chief 

 being that the former is based on the natural model, that it deals with the 

 products of tissue-change, that the right organisms are employed, and that it 

 is easier to regulate dosage. 



The valuable suggestion contained in this book is that in auto-inoculation 

 action is taken against the products of tissue-destruction which result from 

 bacterial infections. The details of the accounts of immunisation and auto- 

 inoculation are open to criticism, and the language throughout is somewhat 

 obscure. 



The interpretation of temperature charts is a highly controversial subject, and 

 even if the author's view be accepted a chart appears to be more interesting 

 as a record than useful as a guide. 



With the views expressed on the advantages of auto-inoculation we are only 

 in partial agreement. Because auto- inoculation occurs in Nature and frequently 

 leads to recovery it does not follow that it is the best artificial method. The 



