G. H. P.

Transacti ons British My cological Society

REVIEW.Principles of Soi l 111icrobiology . By SELMAN A. W AKSMAN. Bailli ere , Tindall

and Cox : London . I927. pp . xxviii + 89 7· Price 45s.This book of nearly nin e hundred pages hails from the United States of

America and is dedi cated to the two pion eers, Beijerinck and W ino gradsky,both now in their seven t ies. It is divided into four main parts of uneq uallength whi ch dea l, in a t otal of thirty-two chap te rs , with the occurrence anddiffe rentiation of microorganisms in the soil , their isolation, identificationand cultivation , th eir chemical ac tivit ies and with soi l microbiological pro­cesses and soil fertility.

The book is frankly a compilation and covers a great deal of gro und . Theauthor has wisely a va iled himself of the services of various specia lists, in hisown and in other countries, for reading and criticising many of the chapt ers,and presumably he has profited thereby. In spite of this, howev er, there areoccasional slips su ch as on p . 236 where the potato Wart Disease producingorganism iSy ncby trium. endobioticums is reckoned amo ngst t he Myxomycetesand on p. 276 wh ere Rhieoctonia is said t o belong t o the Asco mycetes. Itmay be not ed here, also, that proof-reading has been by no means perf ect , fort yp ographical erro rs occur more frequently than they sho uld.

T he author h imse lf has paid sp ecial attenti on to soil Actinomycetes and hasp ub lished sev eral mem oirs on the subject. P lant pathologist s, and esp eciallyt hose interested in the Sca b diseas es of potatoes a nd ot her crops, will thereforewelcome the account give n of t hese or ganisms in chapte r XII . On p . 292 itis st a t ed that" The term colony is used incorrectly in designating a mass ofgrowth of an actinom yces, sin ce it is merely a mass of mycelium developingout of a sin gle spore , and not a colony in t he sense of bact erial growth." Thisis pe rfectly t rue , and deser ves the attention of mycologist s in con nection withgroups of or ganisms ot her than the Actinom ycetes.

In dealing with the effec ts resu lting from partial soil ste rilisat ion it is sati s­factory to find th at the" protozoan theory of soil fertilit y " - abo ut which somuch has been heard in th is cou ntry t hat one began t o wonder whether itssponsors had not deluded themselves int o believin g that it was somethingmore than a theor y- tak es it s proper place in the ranks a long wit h othertheories that have been advanced t o exp lain thc facts, none of wh ich , however ,appears to be quite adeq ua te.

In t he secti on (p. 806) dealing with plant diseases caused by fu ngi foundin the soi l, a fte r mentioning Fusarium radic icola a nd R hizoctonia Solani it isstated that Phytophth ora infes tans can live saprophytically in the soil on oldpartially decomposed plants, and the work of Miss de Bruyn in H olla nd iscited. Such a sta tem ent is apt to be mis leading, for the reader mig ht supposet hat the organism cau sing the potato blight is a more or less commo n soi linhabita nt . It needs to be emphasised that the work was done with cultu resof the fungus in sterilised soil, and it wa s ass umed t hat t here was no differencein the beh av iour of t he fun gus towards sterilised a nd unsterilised soil , anassumption which man y will think totally unwarr anted .

The last chapter of t he book is devoted t o the history of soi l microbiology,its past, pres ent and future, a nd is, perhaps, a little di sappoint ing ; for, af t era while, it becomes not much mo re t han a catalogue of names and dates ; ina mer e nine pages, however, it was scarcely possible t o develop the storymo re adequately .

The book as a whole may be regarded as a serious and prais eworthy att emptto su rvey a very wid e field ; and although not without certain defects it willdoubtl ess be found of considerable value by students and research workers .E very page is provided with footnotes referring t o the relevant lit era t ure,which, as is well kn own, is widely distributed in a multitude of publications.Furthermore, a twenty page inde x of authors is supp lied at t he end. Thebook is, in fact, an up -to-d ate summing up of the vast amount of literatureon t he subject of soil microorganisms and as such will be found of very con­siderable value for refer ence purposes.