October 7, 1920] 



NATURE 



^77 



nervous system of invertebrates, for, as the 

 author remarks, we have as yet only an imperfect 

 conception of the various conduction paths in the 

 ganglia of the earthworm's nerve-cord, although 

 these ganglia have been investigated more than 

 any other part of the nervous system of any 

 invertebrate. J. H. A. 



A Guide to the Old Observatories at Delhi; 

 Jaipur; Ujjain; Benares. By G. R. Kaye. 

 Pp. vii + io8 + xv plates. (Calcutta: Superin- 

 tendent Government Printing, India, 1920.) 

 Price 3s. 6d. 



This little book is an abstract of the larger pub- 

 lication on the same subject which was reviewed 

 in Nature, vol. ciii., p. 166. It is evidently 

 intended for travellers who have seen one or more 

 of these curious and gigantic instruments and 

 wish to know something about their origin. All 

 the tabular matter and similar details have been 

 omitted, while the clear descriptions and some of 

 the excellent pictures have been retained. We 

 could have wished that the author had omitted 

 from this guide-book his remarks about the sup- 

 posed scientific knowledge of Jai Singh. It 

 cannot be denied that this man, living in the 

 eighteenth century, not only was quite unaware of 

 what had been done in Europe during the previous 

 two hundred years to improve the construction 

 of instruments, but also did not even make the 

 .slightest advance on the work of the Greek and 

 Arabian astronomers. All he did was to copy 

 some instrumental monstrosities erected at 

 Samarkand three hundred years before his time, 

 and it is no wonder that little or no use was ever 

 made of them. 



(i) Reports on Hides and Skins. Pp. ix+123. 

 (2) Reports on Oilseeds. Pp. ix+i4g. (Im- 

 perial Institute. Indian Trade Inquiry.) 

 (London : John Murray, 1930.) Price 6s. net 

 each vol. 



In 1916 the Imperial Institute Committee for India 

 was invited to inquire into the possibility of the 

 increased use of Indian raw materials within the 

 Empire. Various committees were set up to deal 

 with the principal groups of materials selected for 

 the inquiry, and the present volumes are the re- 

 ports of those dealing with hides and skins and 

 with oil-seeds. In the report on the former 

 materials (i) it is shown that the pre-war trade in 

 "kips" was almost entirely with Germany and 

 Austria. During the war the Government was 

 .iblc to utilise most of the rhaterial produced, and 

 proposals arc made for preventing the return of 

 the trade to the countries of Central Europe. For 

 this purpo.sc a preferential export duty is pro- 

 posed ; also the leading tanners of the Empire 

 have been approached, and they have agreed that 

 they can utilise all the hides produced bv India. 

 Suggestions are also made for improving the 

 quality of the hides. Statistics showing the ex- 

 port trade between 1910 and 1918 in raw cow- 



NO. 2658, VOL. 106] 



hides, buffalo hides, and goat and sheep skins have 

 been inserted. The report of the committee deal- 

 ing with oil-seeds (2) discusses the position of the 

 trade in that commodity with England, Germany, 

 and France at some length. It is pointed out that 

 there is likely to be a serious shortage of fats in 

 the world, and a system of rationing is recom- 

 mended in order to secure adequate supplies to 

 Great Britain and her Allies. It is further sug- 

 gested that a preferential import tax on vegetable 

 oils should be levied at our ports, and that there 

 should be co-operation between the seed-crushers, 

 the banks, the Government, and the transport com- 

 panies with the view of facilitating the transit or 

 re-export trade and of reducing the cost of pro- 

 duction. Statistics for 1895 onwards of the trade 

 in ten different kinds of oil-seeds produced in 

 India are given. 



Immunity in Health: The Function of the Tonsils 

 and other Subepithelial Lymphatic Glands in the 

 Bodily Economy. By Prof. K. H. Digby. 

 Pp. viii-fi30. (London: Henry Frovvde, and 

 Hodder and Stoughton, 1919.) Price 8s. 6d. 

 net. 



In this book Prof. Kenelm Digby discusses the 

 functions which may be performed by such struc- 

 tures as the tonsils, the intestinal lymphoid fol- 

 licles, and the vermiform appendix, all of which 

 are essentially lymphoid organs grouped by the 

 author under the term "subepithelial lymphatic 

 glands." The disadvantage of these structures in 

 the body is their proneness to bacterial invasion 

 and infection. The tonsils and appendix are, 

 moreover, frequently removed by operation with- 

 out any apparent effect due to their loss. The 

 utility of these glands has, therefore, been 

 doubted, and the appendix is commonly regarded 

 as a vestigial organ in process of reduction. It 

 is noteworthy that all these structures are located 

 in situations — mouth, throat, and intestine — 

 where large masses of bacteria are present, that 

 they freely ingest bacteria, and that they occur 

 only in birds and mammals, the highest and most 

 differentiated of animals. 



The hypothesis put forward by the author of 

 the use of the subepitlielial collections of lymph- 

 oid tissue is that they play an important function 

 in immunising the body against pathogenic bac- 

 teria in proximity to the tissues — they are im- 

 munising stations, so to speak. The several 

 tonsils form a protective circum-pharyngeal ring, 

 and the PeyCr's patches, appendix, and solitary 

 follicles are distributed over the intestine — localir 

 ties which are most in need of protection from 

 bacterial invasion. In the stomach, on the other 

 hand, lymphoid structures are almost absent, but 

 here the acid nature of the .secretion is sufficiently 

 protective without their aid. The argument is 

 sustained by a number of anatomical, micro- 

 scopical, and clinical observations and data, and 

 we think the author has made out a good case. 

 The book is illustrated with several original 

 drawings and diagrams. R. T. H. 



