458 



NA TURE 



[June i6, 1910 



Apart from the relatively minor points just men- 

 tioned, the chart will probably prove of considerable 

 service to lecturers of chemistry by relieving them of 

 the necessity of preparing the large diagram illustrat- 

 ing the periodic classification which is now essential 

 for class teaching of chemistry. 



Leitfaden der Biologic fUr die Oberklassen hoherer 

 Lehranstalten. By Dr. O. Rabes and Prof. E. 

 Lowenhardt. Pp. x + 248. (Leipzig : Quelle and 

 Meyer, 1910.) Price 3 marks. 



This book is intended for the use of pupils who have 

 already had a certain amount of biological training 

 in school. It covers a very great deal of ground in a 

 ver)' su{>erficial manner, but in the hands of a capable 

 teacher it should serve as a good foundation for an 

 extremely interesting course of general biology. It 

 commences, in what we conceive to be a very logical 

 manner, with a general account of the cell, but the 

 fact that this occupies less than one page is typical 

 of the superficial method of treatment. A few uni- 

 cellular organisms are then dealt with, chief!}' from 

 the physiological point of view. 



The general physiology of multicellular organisms 

 comes next, and the first part concludes with a de- 

 scription of seventeen types of plants and animals, 

 ranging from bacteria to the bean in the vegetable 

 series, and from Paramoecium to the rabbit amongst 

 animals. The descriptions and illustrations of these 

 seventeen types occupy twenty-six pages ! The type 

 system has become almost vestigial. 



The second part of the book is devoted to the 

 dependence of organisms upon their environment 

 (cecology), including geographical distribution and 

 an appendix on the geological history of plants and 

 animals and the theory of descent. The third part 

 deals with man, mainly from the physiological, 

 ethnological, and palaeontological points of view. 



The book is very copiously and admirably illus- 

 trated, but four or five volumes of its size would be 

 required to do justice to the subject-matter. 



Tarr and McMurry's Geographies. The Five Book 

 Series. First part. Home Geography. Pp. xi-f-ii2. 

 Price 25. 6d. Second part. The Earth as a Whole. 

 Pp. ix+i68. Price 25. 6d. Third part. North 

 America. Pp. xix + 469. Price 45. 6d. Fourth part, 

 General Geography, South America and Europe. 

 Pp. xvii + 378. Price 35. Fifth part, Asia and 

 Africa. Pp. ix + 214. Price 2s. 6d. By Prof. Ralph 

 S. Tarr and Prof. Frank M. McMurry. (New 

 York : The Macmillan Co., 1908, 1909, 1910.) 



The authors, who are well-known writers on geo- 

 graphical subjects from the point of view of the school, 

 have evidently taken great pains to adapt themselves 

 to the needs and capabilities of young pupils. On the 

 whole, they have been successful in producing a good, 

 workable course of school geography. Written 

 primarily for American boys and girls, great promi- 

 nence is given to the geography of the United States 

 and less importance to that of the British Isles. 

 When it is pointed out, however, that while 230 pages 

 are devoted to the United States, the British Isles 

 are disposed of in 35 pages, it will be seen that the 

 volumes are hardly suitable for adoption as class- 

 books in our schools. But they should prove of great 

 assistance to our teachers in showing how geography 

 may be taught in a way to arouse interest and develop 

 thought. Every part is well and profusely illustrated 

 with views, diagrams, and photo-relief maps. In 

 addition there are numerous coloured political maps, 

 but no use appears to be made of coloured orographical 

 maps. 



NO. 2120, VOL. 83] 



LETTERS TO THE EDITOR. 



[The Editor does not hold himself responsible for opinions 

 expressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part of Nature. 

 No notice is taken of anonymous communications.] 



Koch's Discovery of tne Method of Plate-culture of 

 Micro-organisms. 



Reading the interesting notice of Robert Koch which 

 appeared in Nature of June 2, I was reminded of an 

 incident mentioned concerning his early scientific career in 

 the preface to Cohnheim's " Gesammelte Abhandlungen." 

 Cohnheim, the pioneer of what has been sometimes termed 

 physiological pathology, died in 1884 at the early age of 

 forty-five. The preface to his collected works, published 

 in the following year, contains a charmingly written 

 memoir of him from the pen of his friend W. Kiihne, the 

 accomplished Heidelberg physiologist. The obituary notice 

 of Koch in Nature rightly stressed the immense value to 

 bacteriology of his invention Qf the plate-method for 

 obtaining pure cultures of micr,9ff);:ganisms. The incident 

 reported by Kiihne in his memoir of Cohnheim has refer- 

 ence to that, and to Cohnheim's contact with Koch in 

 consequence of it in the year 1875. At that time Cohn- 

 heim was already full professor of pathology in the Uni- 

 versity of Breslau, and his brilliance as an investigator 

 was already attracting to his laboratory men of promise 

 from all parts. Koch, on the other hand, was in country 

 practice in Silesia, and quite unknown to the scientific 

 world. Koch's discovery of the plate-method led to Cohn- 

 heim's discovery of Koch, and the enthusiasm and remark- 

 able prevision at once shown by the young professor of 

 pathology regarding his unknown compeer, only two years 

 younger than himself, are strikingly told by Kiihne. His 

 words run : — 



" In November, 1875, Robert Koch wrote begging Cohn 

 the celebrated botanist. Professor of Botany in the Uni 

 versity, to look at cultures of anthrax bacilli which he 

 (Koch) had prepared pure ; and for that purpose^ Koch 

 went to Breslau to see him. Cohn had had many tiresome 

 and disappointing experiences of cultures of pathogenicL 

 organisms brought to him with the assertion that theyfi 

 were of pure and isolated species; in the present instance 

 he naturally felt at first little confidence, but after inter- 

 viewing Koch he sent a messenger to the Pathologica' 

 Institute asking someone to come over because a visitor 

 Dr. Koch, had something to show which was ' quite right[; 

 and very interesting.' In the Pathological Institute^j 

 Weigert,' Cohnheim's assistant, was about to perform ar 

 autopsy ; Cohnheim himself therefore went across to the 

 Botanical Laboratory, and when he returned he said, ' No\^ 

 leave off everything here and go over to Koch. The mar 

 has made a tremendous discovery, which for its simplicit} 

 and its accuracy of method deserves admiration all thi 

 more because Koch himself is living entirely remote fron 

 scientific intercourse, and has done it all by himself am 

 finished it right out. There is nothing whatever to ad(i| 

 to it. I regard it as the greatest discovery in the whol''v 

 field of bacteriology, and I believe Koch will surprise uji 

 all in times to come with further discoveries and put ul'i 

 all to the blush for our laurels.' " _ _ il; 



Perhaps this picturesque reference to a turning point i:|| 

 Koch's earlier career, being contained in a volume littlj.-; 

 likely to be sought for information about him, migh.t 

 escape the notice of some whom it would interest, especiaU|i 

 at the present time. C. S. Sherrington. [S 



The University, Liverpool. 



Crocodiles and Sleeping Sicknese. . 



In the obituary notice of Prof. Robert Koch in Natof,. 

 of June 2 (p. 404), it is stated that " Koch suggested th.'i- 

 the crocodile might be the reservoir host of the trypancj. 

 some that gives rise ... to sleeping sickness." This ;. 

 a statement that has been made very often, especially ijv 

 the daily Press, but which I, for my part, have never bee! 

 able to ' verify, although I have some acquaintance wit 

 Koch's writings on the subject of sleeping sickness. Sin«r 

 this idea has been attributed so often to Koch, it is doubfs? 



mM 



