December i , 1923] 



NA TURE 



1^1 



cable Diseases, Laboratory, Vital Statistics, Child 

 Hygiene, Venereal Diseases. This table is followed by 

 a valuable table by Dr. Chapin giving the relative value 

 or "marks" of different branches of public - health 

 work. It will surprise some English administrators to 

 find plumbing and nuisances credited with 20 marks 

 out of a total of 1000, while control of nostrums is given 

 50 marks, educational measures 80, and anti-tuber- 

 culosis work 140. There is much to be said for this 

 American apportionment of merit. A number of ap- 

 pendices give details as to industrial hygiene, the em- 

 ployment of children, form of report of an industrial 

 nurse, the Workmen's Compensation Act, housing, etc. 

 The book can be recommended as containing a review 

 of recent information on most branches of preventive 

 medicine, which would be most difficult to obtain else- 

 where, except by reference to many documents. 



Our Bookshelf. 



Les PMnomenes thermioniqiies. Par Eugene Bloch. 



(Recueil des Conferences-Rapports de Documentation 



sur la Physique. Vol. 4, i"" Serie, Conferences 9, 10. 



£dite par la Societe Journal de Physique) Pp. iii. 



(Paris : Les Presses universitaires de France, 1923.) 



10 francs. 

 Electric conductivity and other effects produced in 

 the neighbourhood of hot bodies are generally called 

 " thermionic " phenomena. The author gives an 

 interesting and clear account of several of the laws in 

 connexion with effects that have recently been dis- 

 covered by 0. W. Richardson and others. In spite of 

 the great progress that has been made, there is no 

 indication that this mine of research is approaching 

 exhaustion. New practical applications are being con- 

 tinually found. Thermionic valves are now being 

 made by hundreds of thousands for use in radio com- 

 munication, radiography (X-ray work), and for rectify- 

 ing alternating currents. Notwithstanding the great 

 practical use that is made of thermionic phenomena, we 

 are still far from seeing how they explain contact 

 difference theories or thermo-electricity. In particular, 

 the theory of thermionic emission in gases gives rise 

 to great difficulties. We have still to explain many 

 apparent experimental contradictions. The serious 

 study of ionisation potentials and of resonance founded 

 on thermionic emissions has barely begun. As time 

 elapses the theoretical field becomes more complex, but 

 the possibilities of valuable discoveries become greater. 



The Outline of the World To-Day. Edited by Sjr 

 Harry Johnston and Dr. L. Haden Guest. (To be 

 completed in about 24 fortnightly parts.) Part i. 

 Pp. 40. (London : George Ncwnes, Ltd., 1923.) 

 IS. 2d. net. 

 There should be a demand fur a work ot tliis nature, 

 which aims at giving " a clear and definite impression 

 of the immense variety of the life and romance, the 

 natural beauties and treasures, of other lands." The 

 first issue contains the greater part of the section dealing 

 with France, and is copiously illustrated witli well- 

 chosen photographs, colour plates, and coloured maps 

 by Bartholomew. The letterpress is vivid, accurate, 



NO. 2822 VOL. I 12] 



and sufficiently critical to give it value, but there is 

 little attempt to describe or explain the scenery, and 

 the maps have the defect of showing no physical 

 features. Some attention to physical geography would 

 not be amiss. There is no indication of the arrange- 

 ment of the work except that it will " concentrate 

 on the interesting side of nations and their lives, dealing 

 with mankind at home . . . their joys and pleasures, 

 their sports, their pageants, and their ideals." The 

 authors of the various articles are not stated, but the 

 names of the editors are sufficient guarantee that 

 high authorities will be chosen. So far as can be 

 judged from the first number, the work should prove 

 of value in spreading a knowledge of the ways of other 

 nations and encouraging an understanding of their 

 ideals and ambitions. 



The Banyankole : the Second Part of the Report of the 



Mackie Ethnological Expedition to Central Africa. 



By the Rev. John Roscoe. Pp. xii+ 176 + 31 plates. 



(Cambridge : At the University Press, 1923.) 15s 



net. 

 In the second volume of the report of the Mackie 

 Ethnological Expedition to Central Africa, Mr. Roscoe 

 again deals with an immigrant nomadic pastoral 

 people, ruling an earlier, or original, agricultural 

 group. The Bahuma belong to the same stock as the 

 neighbouring Baganda and Bakitara, but represent 

 an earlier settlement in the Lake regi">n. They are 

 even more strict than the Bakitara in the observance 

 of milk customs, and owing to their repugnance to 

 intermarriage with their serfs, who lived on vegetable 

 food, they are racially purer than most pastoral 

 peoples of this area. Apart fruin Uu' description of 

 the ritual of the milk, which necessarily occupies a 

 position in the book commensurate with its prominence 

 in the life of the people, Mr. Roscoe's minute account 

 of the Banyankole is a piece of work the value of which 

 to the ethnologist it is difficult to overestimate. Not 

 only is the culture he describes rapidly passing away, but 

 also it embodies — as for example in its totemic system 

 and belief in the reincarnation of members of the royal 

 family in the forms of various animals — elements which 

 are of great importance in the study of the develop- 

 ment of custom and belief. 



The Unconscious Mind : a Psycho-Analytical Survey. 



By Dr. S. Herbert. Pp. vii-h230. (London : A. 



and C. Black, Ltd., 1923.) 6s. net. 

 The output of psycho-analytic literature is always on 

 the increase. This volume is an attempt to give a 

 systematic account of the Unconscious on Freudian 

 lines ; and it follows the usual plan upon which such 

 works are written, containing considerable illustration 

 of theory from case-histories, examples of myth, wit, 

 art, and the like. There is a good chapter on " Theories 

 of the Unconscious," in which the leading views are 

 stated and criticised with — naturally enough — a strong 

 Freudian bias. On the whole, '* The Unconscious 

 Mind " is a simple and straightforward presentation 

 (so far as the subject-matter permits of simplicity and 

 straightforwardness) of the doctrine of the Viennese 

 school ; and can be recommended for the literary form 

 of its presentation as well as for being — what it claims 

 to be — " a general outline of our knowledge of the 

 nuconscious, as hitherto ascertained." 



