March ii, 1920] 



NATURE 



33 



Tropical Medicine. 



Fevers in the Tropics. By Sir Leonard Rogers. 

 Third edition. Pp. xii + 404 + 9 plates. (Oxford 

 Medical Publications.) (London : Henry Frowde 

 and Hodder and Stoughton, 1919.) Price 305. 

 net. 



THIS, the third edition of Sir Leonard Rogers's 

 well-known work, has, in our opinion, been 

 improved by the pruning process to which it has 

 been subjected, but it may be doubted whether 

 the process has been sufficiently -drastic, and per- 

 sonally we should breathe a sigh of relief if the 

 " Burdwan fever " and some other hardy peren- 

 nials were finally laid to rest. The distinguishing 

 character of the author's method is the great 

 importance which he attaches to the study of tem- 

 perature charts and to leucocyte counts as means 

 of diagnosis, with the result that, perhaps unwit- 

 tingly, he scarcely emphasises sufficientiy that in 

 diseases of a parasitic nature these can be only 

 of secondary importance. Thus "a great leuco- 

 penia" may be "greatly in favour of kala-azar," 

 but a diagnosis can be made with certainty only 

 in one way, viz. by finding the parasites ; and as 

 it is not stated whether this has been done in the 

 many examples, accompanied by charts, given of 

 "this disease," we are uncertain whether they 

 really are "this disease," or examples of another 

 disease, possibly the 43 per cent, of "kala-azar" 

 cases in which parasites are not found, and which, 

 for all we know to the contrary, may also show 

 "a great leucopenia." 



The author's exposition of these indirect 

 methods of diagnosis consumes, we think, too much 

 space, so that pathological histology, which should 

 form our only certain basis for the interpretation 

 of symptoms, receives rather scant attention. 

 Thus nothing is said of the changes in American 

 trypanosomiasis, and those of malaria and black- 

 water fever, for example, are very incompletely 

 described. 



Again, although twenty-one pages are allotted to 

 a discussion of pre-suppurative hepatitis, we our- 

 selves do not know what a liver in this condition 

 would lopk like, as no post-mortem descriptions 

 are given. 



Under blackwater fever it is stated that "the 

 parasite most commonly met with is the malignant 

 tertian, the other forms being rare." If the other 

 forms are rare, as in a malaria district like West 

 Africa, or the Duars.in India, this is only what 

 one would expect ; consequently, the statement has 

 little significance; but if we are considering a 

 district like the Panama Canal, where the simple 

 tertian parasite forms about 26 per cent, of the 

 malaria cases, then this statement is not true, for 

 NO. 2628, VOL. 105] 



we find that about the same percentage — viz. 24 

 per cent. — of the blackwater cases show simple 

 tertian parasites, and on the Madera River, Brazil, 

 where simple tertian forms about 30 per cent, of 

 the malaria cases, the percentage for the black- 

 water cases is 42 per cent. 



On p. 66 we find a common error repeated — 

 viz. that tsetse-flies in the resting position can 

 be distinguished from all other flies by the wings 

 "closed . . . like the blades of a pair of 

 scissors " ; and on p. 86, probably through a lapse 

 of memory, it is said that tartar emetic is specific 

 for American trypanosomiasis ; unfortunately, it 

 appears to have no action on it. Misprints are 

 rather numerous : Crintridia for Crithidia, Trio- 

 mata for Triatoma, lenticularis for lectularius, 

 sodia for sordida, tropical for tropica, galinarum 

 for gallinarum, etc. 



Readers who do not already know the work will 

 find something different from the ordinary text- 

 book, but we think they would be glad if the 

 author's well-known clinical enthusiasm could 

 express itself more tersely and — dare we say it? — 

 more critically. J. W. W. S. 



Practical Chemistry. 



(1) A Text-book of Quantitative Chemical Analysis. 

 By Dr. A. C. Cumming and Dr. S. A. Kay. 

 Third edition. Pp. xv-f 416. (London : Gurney 

 and Jackson ; Edinburgh : Oliver and Boyd, 

 1919.) Price 125. 6d. net. 



(2) A Course of Practical Chemistry for Agri- 

 cultural Students. Vol. ii. Part i. By 

 H. A. D. Neville and L. F. Newman. Pp. 122. 

 (Cambridge : At the University Press, 1919.) 

 Price 55. net. 



(3) Chemical Calculation Tables: For Laboratory 

 Use. By Prof. H. L. Wells. Second edition, 

 revised. Pp. v-f43. (New York: John Wiley 

 and Sons, Inc. ; London : Chapman and Hall, 

 Ltd., 1919.) Price 65. 6d. net. 



THERE is always a tendency among students 

 of analytical chemistry to value their work 

 by its quantity and the nearness of their results 

 to what is assumed to be correct, and in this they 

 are often encouraged by those who have the 

 direction of their studies. They do as they are 

 told in their text-book — weigh out so much, dis- 

 solve in 200 c.c. of water, add 20 cc. of a stock 

 reagent, heat to boiling, wash three times by 

 decantation, and so on; and in the end, though 

 they get an excellent result, they have learned not 

 so much chemistry as if they had made an apple 

 dumpling by intelligently following the instructions 

 of a cookery book. 



