December 8, 1923] 



NA TURE 



«43 



Research Items. 



The Causal Organism of Braxy in Sheep. — 

 There has been much dispute regarding the essential 

 symptoms and the causal organism of braxy. What 

 may be called the old school considered the disease 

 to be due to an anaerobic, motile, spore - bearing 

 bacillus, giving rise to an inflammatory condition 

 of the fourth stomach. But the latest review of 

 our present state of knowledge, by Dr. J. P. McGowan 

 (Centralb!. f. Bakteriol., Parasit., und Infektionskr., 

 Jena, Bd. 91, 1923), shows that, in face of the criticism 

 of continental workers and of the author himself, 

 this view must be abandoned, for feeding or inocula- 

 tion with the alleged causal organism fails to produce 

 braxy. It would also appear that the sjnnptoms 

 usually considered to be those of braxy are in reality 

 very rapid post-mortem putrefactive changes. Ex- 

 amination of very fresh carcases shows the abundant 

 presence in pure culture of Bacillus bipolaris septicus 

 ovium, inoculation with whifh reproduced the disease ; 

 and this would indicate that braxy is a hyperacute 

 form of haemorrhagic septicaemia. Sheep are pre- 

 disposed to attack under conditions of lowered 

 resistance, often dependent upon climatic factors, 

 such as the presence of a large quantity of frosted 

 grass in the food, or exposure to severe day and night 

 fluctuations of temperature. Sheep which are feed- 

 ing poorly seldom suffer from the disease, and to this 

 fact the author attributes the success of the well- 

 known pig-dung drench and of the " vaccines " 

 prepared from non-causal bacilli, since both treat- 

 ments throw the sheep seriously out of condition. 



Insulin. — The chemLsty of insulin is described in 

 an article by Mr. Norman Evers in the Chemical Age 

 for November 3. So far back as 1885 Mering and 

 Minkowski noticed that complete extirpation of pan- 

 creas from dogs was followed within a few days by 

 diabetic symptoms similar to those observed in human 

 beings. Lepine suggested that the pancreas gave 

 some secretion which controlled carbohydrate meta- 

 bolism, and this view gained ground. Schafer sug- 

 gested the name " insuline " for the secretion pro- 

 duced by certain groups of small cells in the pancreas. 

 Many attempts were made to prepare an extract of 

 the pancreas which on injection would reduce the 

 blood sugar of a diabetic patient, but it was left for 

 Drs. Banting and Best, working under Prof. J. J. R. 

 Macleod at Toronto University, to crown these efforts 

 with success. Mr. Evers describes the original 

 method of extraction in some detail, and considers 

 the subsequent improvements ; he also treats of the 

 purification, chemical properties, and of the other 

 sources of the substance. Apparently, for the present, 

 ox and pig pancreas are the only available economic 

 sources. It will be recalled that an article by Prof. 

 J. J. R. Macleod describing the action of insulin 



(jeared in NAXUREof October 27, p. 625. 



Iropical American Ascomvcetes. — Among the 

 < omycetes of Tropical America are several puzzling 

 lorms of Discomycetes, which in habit recall rather the 

 Basidiomycetous genus, Auricularia. Just before his 

 death the late Prof. Durand had revised a number 

 of the.se forms, and his findings have been published 

 by Dr. Roland Thaxter, with some notes and two 

 plates of figures added. The long-cstablislied genus, 

 Midotis Fr., is now clearly characterised for the first 

 time, whilst .some other curious .species, including 

 some previously grouped under (■onfierites Mont, are 

 now placed in a newly formed genus. lonomidotis 

 T^urand. Seven species of this new genus are described, 

 la key supplied for their identification. 



NO. 2823, VOL. I 12 I 



Control of Disease in the Palmyra Palm. — 

 Something of the problem involved in carrying out 

 remedial methods in phytopathology is to be seen in 

 the report by W. McRae, appearing in the Memoirs 

 of the Department of Agriculture in India, volume 12, 

 No. II, July 1923. In 1905 Dr. E. J. Butler 

 identified Phytophthora palmivora, Butl., as the cause 

 of the serious disease of the Palmyra palm, Borassus 

 flahellifer Linn., occurring in the Madras Presidency. 

 This palm is of great importance to the native 

 community both for its fruit and for its use as the 

 source of a fermentable liquid used in the preparation 

 of toddy. For the latter purpose the leaves at the 

 apex of the shoot are cut. Older leaves are some- 

 times cut also for use either as fuel or as a source of 

 fibre. Control of the disease has involved the 

 cutting, removal, and burning of the green tips of 

 diseased trees and then, as experience showed it 

 possible, the removal of outer diseased leaves from 

 less severely affected trees, which then frequently 

 recovered from the disease. The author concludes 

 that, during the fifteen years in which the control 

 operations which he reviews have been in progress, 

 some three-quarters of a million palms have been 

 saved, and he affirms definitely that the disease has 

 been reduced from a grave menace in 1908 to 

 a controlled problem at the present time. The 

 operations, carried out by native workers under the 

 supervision of a special staff recruited from the 

 Revenue Branch of the District Administration, are 

 estimated to have cost 20,000/. for the period 1916- 

 192 1. Until the application of the Pest Act, every- 

 thing had to be done with the acquiescence and 

 co-operation of the villagers, the result being so careful 

 an attention to propaganda and education in the 

 rea.sons for remedial measures that during the first 

 two years' operation of the compulsory clauses 

 contained in the Pest Act only one prosecution has 

 proved necessary. 



The Theory of Isostasy. — At the meeting of the 

 Royal Geographical Society on November 12, two 

 papers discussing the theory of isostasy from very 

 divergent angles were presented. The briefer one, 

 " Doubts and Suggestions on Terrestrial Isostasy," by 

 Captain Alberto Alessio, is critical of Hayford's 

 method of treating Pratt's hypothesis : his assertion 

 that the field of force of gravity, being observed only 

 at a limited number of points, can be produced in an 

 infinite variety of ways by appropriate distributions 

 of density may be assented to ; but he brings forward 

 no arguments of sufficient weight to explain away the 

 value of Hayford's simple general hypothesis as to the 

 distribution of density under mountain or oceanic 

 regions, as a means of accounting for variations in the 

 gravitational field. The second paper, on " Abnormal 

 Densities in the Earth's Crust disclosed bv Analvsis 

 of Geodetic Data," is by Prof. W. Bowie, of the United 

 States Coast and Geodetic Survey, who has continued 

 Hayford's isostatic researches. It is a valuable and 

 interesting r^sum^ of the present state of the theory, 

 indicating both its many successes and the extent to 

 which it is to be regarded as a simplification — for 

 purposes of preliminary analvsis and computation — 

 of the probable real facts. The anomalies or differ- 

 ences of the observed gravity data from the values 

 calculated by Hayford's method are shown to be much 

 less than those from the values calculated by Bouguer's 

 method, in which no account is taken of the isostatic 

 compensation. It is al.so shown that the Bouguer 

 anomalies increase rapidly for elevated .stations, while 

 the " i.sostatic " anomaiies show a purely normal 

 accidental distribution. Even so, a considerable class 



