October lo. 1907J 



NATURE 



607 



changing from the spectrum to the coinparison lamp. This 

 eliminated trouble due to drift. Measurements were made 

 both with approximately monochromatic light in the 

 neighbourhood of 0-54 /i. and in white light obtained by 

 widening the slit until the whole of the light within the 

 visible limits was collected at the bolometer. The result 

 obtained for the mechanical equivalent was 006 watt per 

 candle for the yellow-green light; for white light obtained 

 from an arc the mechanical equivalent was 008 watt per 

 candle, and from a Nernst filament as source 01 2 watt 

 per candle, the latter result agreeing almost exactly with 

 that obtained by Angstrom for the light of the Hefner 

 lamp. The ideal source of white light should therefore 

 gi\e somewhere about ten candles per watt, and a mono- 

 chromatic yellow-grein source nearly seventeen candles 

 per watt. 



June 13. — " On the Identification of Chitin by its 

 Physical Constants." By Miss I. B. J. Sollas. Com- 

 municated by Prof. \V. J. Sollas, K.R.S. 



The determination of the physical constants of chitin 

 forms a useful method of identifying it. The specific 

 gravity of chitin from various sources approximates to the 

 value 1-398, a number which represents the specific gravity 

 of chitin precipitated from its solution in strong acid. 

 The refractive index lies between the limits 1-550 and 



I-557- 



The bristles of Lumbricus, the pupal skin of Pieris and 

 other Lcpidoptera, the radula of Mollusca and the shell of 

 Sepia, when freed from mineral matter and easily soluble 

 organic substances, have specific gravities and I'efractive 

 indices which lie between the same limits as those of 

 chitin from 'various sources. 



June 27. — " The I'ressure of Brro Secretion and the 

 Mechanism of Bile Absorption in Obstruction of the Bile 

 Duct." By Dr. Percy T. Herring- and Dr. Sutherland 

 Simpson. 



The authors find that the maximum pressure attained 

 by the bile in obstruction of the common bile duct con- 

 siderably exceeds the figures given by Heidenhain. In 

 the dog, cat, and monkey the average maximum pressure 

 reached in a 'number of experiments was 300 mm., 

 measured in terms of the height of a vertical column of 

 bile. The highest pressure recorded was 373 mm. bile 

 in a cat. 



When the common bile duct is obstructed the bile 

 escapes from the liver by the lymphatics, and in the cat 

 may be seen in the thoracic duct one hour after obstruc- 

 tion, f*"! 



Evidence is adduced to show that the obstructed bile 

 enters the intracellular plasmatic channels of the liver 

 cells, and passes from them by the natural lymph flow 

 into the lymph channels of the portal spaces. The 

 mechanism of absorption lies in the liver cells, and is not 

 an escape from interlobular bile ducts. 



The intracellular plasmatic channels are held to con- 

 stitute an intermediate system between the blood-vessels 

 and lymphatics of the liver. The " vilal " theory of lymph 

 formation is supported. 



" On the Relation between the Output of L'ric .\cid 

 and the Rate of Heat Production in the Body." By E. P. 

 Cathcart and J. B. Leathes. Communicated bv Dr. 

 C. J. Martin, F.R.S. 



A diet containing no purine bases, free or combined, 

 was taken Jjy one of the experimenters in equal amounts 

 every three hours during the day, and the output of uric 

 acid during each of the periods of tliree hours was deter- 

 mined. In this way the average rate of excretion for 

 each period of the day could be ascertained, as well as 

 the daily total. Exposure to cold for about three hours 

 with no voluntary muscular exertions increased the rate 

 of excretion at the time and for some time after (in the 

 first twenty-four hours nearly 50 per cent, above th<- mean 

 calculated from sixteen successive days), whereas a similar 

 exposure to cold counteracted by muscular activity in- 

 creased it much less (in the first twenty-four hours about 

 15 per cent.), and muscular activity without the stimulus 

 of cold (in heavy clothing) for the same length of time 

 diminished it (in the first twenty-four h(iur> about 30 per 



NO. Ic8o, VOL.. 76] 



cent.). The conclusion pointed to is that the endogenous 

 uric acid is in part, and it may be to a considerable extent, 

 a product of the reaction of the body to loss of heat, and 

 that this reaction consists in some form of activity distinct 

 from voluntary movements of the muscles. 



" Further Studies of Gastrotoxic Serum." By Dr. 

 Charles Bolton; Communicated bv Prof. S. Martin, 

 F.R.S. 



The serum referred to in this communication was pre- 

 pared by injecting the stomach cells of the guinea-pig into 

 the rabbit, the blood serum of the rabbit developing toxic 

 properties for the guinea-pig's tissues. 



It has been shown that the serum contains, not only 

 a precipitin for stomach-cell proteid, but also separate 

 precipitins for other body proteids. The actions of these 

 precipitins overlap to some extent. There is no agglutinin 

 for the stomach-cell granules, the agglutination which was 

 found to occur being brought about by the precipitins. 



The repeated injection of gastrotoxic serum does not 

 produce chronic gastric ulceration, but immunity to the 

 serum is established. The immunity is not only active, 

 but the serum is able to confer passive immunity upon 

 another animal. The tissues of the immune animal are 

 still acted upon by the gastrotoxic serum in the test-tube, 

 the immune substances being present in the blood serum 

 of the animal. 



It has been demonstrated that the necrosis of the mucous 

 membrane of the stomach resulting from the injection of 

 gastrotoxic serum is not directly caused by the serum, 

 but is brought about directly by the action of the gastric 

 juice. The cells are functionally damaged by the serum, 

 which renders them susceptible to the gastric juice. The 

 process is thus one of self-digestion. Hyperacidity of the 

 gastric juice increases the tendency to this self-digestion. 



Received July 20. — " A Preliminary Summary of the 

 Results of the Experimental Treatment of Trypano- 

 somiasis in Rats." By H. G. •Piimmer and J. D. 

 Thomson. Communicated bv Sir Rav Lankester, K.C.B., 

 F.R.S. 



The experiments described were undertaken under the 

 direction of the Tropical Diseases Committee of the Royal 

 Society. 



The strains of trypanosomes used were a nagana from 

 the original strain brought to England, and a surra from 

 Prof. Lingard in India. The nagana strain kills rats in 

 an average time of 5-5 days, and the surra strain in 

 6-9 days. 



Of drugs experimented with, fifteen chinolin compounds, 

 dichlorobenzidine + aridH, trypanroth, arsenious acid, 

 atoxyl, monophenylarsenic acid, nitrophenylarsenic acid, 

 p,aratolvlarsenic acid, and other arsenic compounds are 

 commented upon, and their effects on the development and 

 course of the diseases stated. Of all the arsenic com- 

 pounds, and, indeed, of all substances tried singly, atoxyl 

 had bv far the most favourable action. 



This is the most important substance, so far discovered, 

 in relation to the treatment of trypanosoiniasis. In 

 nagana and surra atoxyl causes the entire disappearance of 

 the trypanosomes front the blood, so that rats inoculated 

 with the blood when it was microscopically free from 

 parasites failed to take the disease ; but the trypanosomes 

 have invariablv recurred, and death was only delayed- for 

 a period varying with the dose, and with the time of 

 commencement of the treatment. 



When atoxvl is given more continuously or more freely 

 than is required, in cases in which there have beeti many 

 recurrences, and probably under some other conditions of 

 which we are ignorant, in a certain small proportion of 

 rats so treated a race of trypanosomes is produced which 

 entirely resists atoxyl, and continues to develop and 

 multiply in spite of continued exhibition of the drug. This 

 strain, when inoculated into fresh rats, retains its resist- 

 ance to atoxyl. Ehrlich, who has produced such a strain 

 in mice, call's them " atoxyl-fest, " and we have obtained 

 this atoxyl-proof variety of trypanosome in rats, both in 

 nagana and surra. 



In human trypanosomiasis the danger of the production 

 of an atoxyl-proof strain will be at once apparent. For an 

 account of the production and behaviour of these atoxyl- 



