Decembee 31, 1915] 



SCIENCE 



937 



what may be regarded as a laudable American 

 aspect, it can scarcely be thought possible that 

 he has not consulted, and consulted freely, 

 every fascicle of Tschirch's "Handbuch" as 

 it has been issued from the press. Though the 

 present unfortunate war is teaching us how 

 derelict we have been in making ourselves inde- 

 pendent of Europe, so far as vegetable drugs 

 are concerned, yet the pharmacognocist, above 

 all, should ever be mindful of the inscription 

 on the Fluecldger medal: Scientia non unius 

 populi sed orhis terrarum. E. K. 



Practical Oil Geology. By Dorset Hager. 



McGraw-Hill, ISTew York, 1915. Pp. xii + 



141; figs. Y6, three being full page, and one 



plate. $2.00 net. 



This handy pocket book puts the stock-in- 

 trade of the petroleum geologist and engineer 

 before the petroleum investor in a way that 

 invites friendship. Further, it lays sound 

 ideas of applied structural and stratigraphical 

 geology before a class which is glad to sub- 

 stitute such revelations for the " luck " of the 

 oil (or water) wizard. 



While the space is so small as to call for 

 brevity at the expense at times of clearness, 

 the numerous excellent cuts — ^most of them 

 evidently the author's — ^more than balance in 

 field ingenuity and the applications of pure 

 geology what may be wanting in the way of 

 academic clarity of statement. 



Only two or three proof errors appear in the 

 text proper. An early second edition for so 

 good a book on a timely subject seems sure, 

 and in the reappearance no doubt there will be 

 weeded out such oversights as : " Igneous 

 rocks, or volcanics," p. 28 ; "a level line in the 

 plane of the horizontal," p. Yl ; " curved axis," 

 fig. 50 and p. 86; Comanchean equivalent to 

 the whole Mesozoic, p. 38. Certainly the errors 

 in Table XI. will not be recopied, nor perhaps 

 that in averaging the viscosity of Oklahoma 

 oils, especially the unfair inclusion of the high 

 viscosity from Wheeler, Table VI. Conven- 

 ience would be served by referring to a figure 

 on a definite page rather than, say, "(See Tig. 

 19, Chapter HI.)." 



Useful adaptations for the layman are : Geo- 



logical Names (Kemp); Mathematical Tables 

 (Hayes); Tests for Oil (Woodruff); Favor- 

 able and Unfavorable Indications for Oil 

 (Craig) ; Definitions of Formation and Mem- 

 ber (Snyder). Other tables and data will serve 

 more technical needs, and the cuts will doubt- 

 less be freely drawn upon by other authors. 



The neat and convenient get-up, and strong, 

 leather binding are characteristic of these 

 publishers. Charles T. Kirk 



State TJniversitt, 

 Albuquerque, New Mexico 



SPECIAL ABTICLES 



ON THE RELATIVE NUMBERS OF RHIZOPODS AND 

 FLAGELLATES IN THE FAUNA OF SOILS 



The investigations upon the protozoan 

 fauna of the soil and its interrelations with 

 the bacterial flora therein contained has opened 

 a new field of exploration and suggested a new 

 line of attack for the problem of " sick soils." 

 The work of Eussell and Hutchinson and 

 their school indicates that the constituents of 

 the protozoan fauna, notably the amcebas, af- 

 fect appreciably the bacterial content of the 

 soils they inhabit, and thus impinge upon 

 some of the problems of fertility. This line 

 of evidence has stimulated many preliminary 

 investigations into the extent, distribution 

 and qualitative make-up of the protozoan 

 fauna of the soil. In many cases these at- 

 tempts at the qualitative determination of 

 these organisms have gone no farther than to 

 record the relative numbers of the individuals 

 belonging to the groups of rhizopods, flagel- 

 lates and ciliates, with occasional question- 

 able identifications of a few genera or more 

 rarely still of species. The purely preliminary 

 status of such investigations is readily in- 

 ferred by those familiar with the fields of bac- 

 teriology, immunity and protozoology. Valid 

 conclusions here can rest only upon a knowl- 

 edge of the fauna which extends to an accu- 

 rate determination of the species concerned 

 and of their feeding habits or symbiotic re- 

 lationships to the bacterial flora, which may be 

 even more subtle than the gross phase of food 

 relations. 



One naturally recalls in this connection the 



