NA TURK 



[January 8, 1903 



An Introduction to Physiology. By William Townsend 



Porter, M.D. Part iv. Physiological Optics. Pp. 



vii + 96. (Cambridge, Mass.: The University Press, 



1902.) 

 The complaint is often made that the laboratory 

 courses in practical physiology can be of little value to 

 the student, in view of the very limited range of the ex- 

 periments regarded as possible for a class, and the con- 

 sequent restriction of the student's attention to one or 

 two chapters of the science. The work before us repre- 

 sents a further step of the creditable effort now being 

 made by Prof. Porter to remove this slur on the 

 practical teaching of physiology and to show that it 

 is possible to give the ordinary student a knowledge 

 of physiology based on his own experience rather 

 than on the mere statement of his teacher or 

 text-book. In this book, comprising less than ioo 

 pages, the student is taught in the first part to de- 

 termine by experiment the main laws of the reflec- 

 tion and refraction of light, and the formation of the 

 image by convex and concave mirrors, as well as the 

 properties of lenses. In the second part, the physical 

 knowledge so acquired is applied to the determination of 

 the optical qualities of the eye, including the mechanism 

 of accommodation. The last three sections deal with 

 the use of the ophthalmoscope, and its application to the 

 estimation of errors of refraction and other defects in the 

 dioptric mechanisms of the eye. 



It would be difficult to imagine a course of study better 

 adapted for the purpose, viz. to give the student of 

 medicine a knowledge which shall fit him for the in- 

 vestigation and diagnosis of the various morbid conditions 

 of the eye. Too many men at present begin to learn 

 their physiological optics only when they are brought 

 face to face with actual cases of disease — a state of 

 things for which the physiological teacher is partly 

 responsible. It is probable that a course such as that 

 laid down by Dr. Porter and extending over about 

 twelve lessons would, if introduced into the London 

 schools, be found to meet a want and would receive 

 appreciation and support. We shall look forward with 

 interest to the appearance of the other parts of this 

 practical physiology, which are to include the special 

 senses, the central nervous system and the whole of 

 chemical physiology. E. H. S. 



The Potash Salts; their Production, and Application to 



Agticulture, Industry and Horticulture. By L. A. 



Groth. Pp. vi + 291. (London : The Lombard Press, 



1902.) 

 THE Triassic strata yielding potash salts occupy a vast 

 area extending through many of the German States. 

 The potash beds are usually at a considerable depth 

 below the surface. The proving of their occurrence is 

 often a matter of considerable expense and uncertainty, 

 and the establishment of mining operations on a com- 

 mercial scale may occupy several years. Germany has, 

 however, nearly a monopoly in potash production, and 

 both the production and prices are regulated by a 

 syndicate ; the general profitableness of the enterprise is 

 thus guaranteed. The working of a commercial trust is 

 well illustrated by the operations of the Potash Syndicate, 

 one object of which is to supply German consumers with 

 a cheap article while much higher prices are charged to 

 foreigners. 



The present book contains a great deal of interesting 

 information as to the potash mines, the mode of working 

 them, the composition of the salts found and the steps 

 taken to prepare various salts for the market. There is 

 also a section of about 100 pages devoted to the use of 

 potash salts for manufacturing purposes, and especially 

 to their use as manures for crops and for garden 

 produce. 



The agricultural section is disappointing. No inform- 



NO. J 732, VOL. 67] 



ation is given as to the large experience gained in 

 Germany on the use of potash manures in various cir- 

 cumstances ; the examples of field experiments quoted 

 are all of them from trials in our own country. The 

 ex»mple» selected are naturally those in which the ap- 

 plication of potash salts has proved a financial success. 

 Potash manures cannot, however, always be used wiih 

 profit ; on many soils they produce no paying result. 

 Every farmer should, therefore, ascertain by actual ex- 

 periment what is the effect of potash on his own fields 

 and crops before venturing on any considerable purchase 

 of potash manure . 



Nothing is said as to the antiseptic effects of potash 

 salts and their hindrance of the decomposition ol farm- 

 yard manure. Nothing is also said as to the danger of, 

 applying them in spring as a top-dressing to a growing 

 crop, due to the injury caused to the leaves on which the 

 salt falls. The differences in the effects of the various 

 potash salts are also not discussed. Notwithstanding, 

 however, the partial character of the book, it is of real 

 value, as it brings together a great deal of information 

 not easily procured. The use of potash manures in 

 agriculture may doubtless be considerably extended, but, 

 as already stated, the deficiency of the soil in potash 

 should in every case be proved by actual experiment 

 before any use of it is attempted on a large scale. 



R. W. 



Advanced Hygiene. By A. E. Ikin, B.Sc, L.C.P., and 



R. A. Lyster, M.B., B.Sc., D.P.H. Pp.300. (London: 



W. B. Clive, 1902.) Price y. 6d. 

 THIS work, though styled "Advanced Hygiene," is only 

 written to provide a second year's course of study of 

 hygiene and public health for those who have mastered 

 the contents of a similar small book by one of the 

 authors, entitled " First Stage Hygiene." 



Though the matter dealt with is of a very elementary 

 nature, its treatment often leaves much to be desired. 

 It is in some places incorrect and in others misleading. 

 To give an illustration, the wash-down water-closet is 

 said to differ from the short hopper in that " the basin 

 and trap are in one piece," which remark embraces the 

 whole description of a wash-down water-closet. 



Many of the illustrations are concerned with sanitary 

 apparatus and arrangements in and about houses, and 

 most of these are badly drawn and otherwise faulty. 

 (Two of them are actually upside-down.) Jennings's plug 

 water-closet is described as a valve water-closet, and 

 Buchan's trap as Buchanan's. The only water filter for 

 domestic use which is illustrated is the Berkefeld, and 

 of this there are no less than six illustrations — all taken 

 from a trade catalogue. 



On occasions, different views are expressed in different 

 parts of the same work. It is stated, for instance, on 

 p. 67, that "it seems to be proved that scarlet fever may 

 be directly transmitted from the cow," while on p. 271 

 it is said that "there is a possibility that cows may suffer 

 from a disease akin to scarlet fever." Further, on p. 140, 

 one reads that "the soil may contain a number of micro- 

 organisms," while on p. 220 it is (correctly) stated that 

 " the surface soil to the depth of 3 or 4 feet swarms with 

 bacteria." 



The analytical notes are of little value, and in many 

 respects they are faulty. In a statement of the parti- 

 culars to be obtained in a quantitative chemical analysis 

 of water, no mention is made of the estimation of 

 chlorine (p. 243). 



Material of Machines. By Albert W. Smith. Pp. v+103. 



(New York : John Wiley and Sons ; London : Chapman 



and Hall, Ltd., 1902.) Price 4s. bd. 

 As the life of a machine tool very largely depends upon 

 the nature and quality of the material used in its con- 

 struction, it is evident that a treatise on this important 



