1 84 



SCIENCE- GOSSIP. 



Isilr^FMSTRY 



conducted by c. ain'sworth mitchell, 

 b.a.oxon., f.i.c., p.c.s. 



Gheen and Blue Modifications op Sulphur. 

 When certain sulphides, snch as those of bismuth, 

 zinc, or cadmium, are heated with a solution of 

 sulphur chloride in benzene, a green powder, con- 

 sisting of almost pure suljihur, is obtained. The 

 product formed in the case of cadmium chloride 

 also contains blue granules ; and Orlow, who has 

 recently studied the phenomenon, suggests that the 

 blue variety of sulphur stands in the same relation- 

 ship to ordinary sulphur as ozone does to ordinary 

 oxygen. 



OccuEHENCE OF ZiNC IN PLANTS. — A series of 

 interesting experiments have been carried out by 

 Ij. Laband to determine the proportion of zinc 

 which plants are capable of absorbing. The plants 

 were grown in a soil containing a large amount of 

 zinc salts, and at the close of the experiments 

 appeared perfectly healthy. When di'ied they were 

 found to contain on the average 0-2 per cent, of 

 zinc. 



Aksenic-fhee Beer. — The Royal Commission 

 appointed last February to in\ estigate the causes 

 of the arsenical poisoning epidemic has issued the 

 first part of its report, in which the causes of the 

 outbreak are dealt with, and methods of prevention 

 discussed. In the main the report confirms the 

 conclusions that had previously been arrived at by 

 independent authorities. As regards the complete 

 elimination of arsenic from beer, it is pointed out 

 that certain tests are so delicate that any beer, how- 

 ever carefully prepared, would show minute traces if 

 examined in sufficient quantity. At the same time 

 the Report says, " in the absence of fuller know- 

 ledge than is at present available as to the possible 

 effects of consumption of mere traces of arsenic, 

 we are not prepared to allow that it would be right 

 to declare any quantity of arsenic, however small, 

 as admissible in beer or in any food, and we think 

 it should be the aim of the manufacturer to exclude 

 arsenic altogether." Recognising the practical 

 difficulty that has arisen through the use of 

 different tests for arsenic, the Commission proposes 

 eventually to prescribe a standard test for beer, 

 fixing a maximum limit, above which there shall be 

 no discussion. 



The Blood op Invertebrate Animals. — In 

 worms and most molluscs the liquid corresponding 

 to the blood of higher animals has reeei\ed the 

 name of haemolymph. It contains white corpuscles, 

 and more rarely red corpuscles, though free oxy- 

 haemoglobin is not infrequently found in solution 

 taking the place of the latter. In certain arthropoda 

 and molluscs, such as crabs, oysters, and snails, 

 the haemolymph is of a bright'blue colour. This 

 is due to the presence of an albuminous colouring 

 matter which takes the place of the oxyhaemo- 

 globin in red blood. This pigment, kiiown as 



oxyhaemocyanin, contains copper instead of iron. 

 It call be partially separated from the haemolymph, 

 but readily dissolves in a dilute solution of common 

 salt. It plays a considerable part in the process 

 of respiration, and when the respiratory oxygen is 

 withdrawn from it, a colourless compound remains, 

 known as haemocyanin, which rapidly becomes 

 blue again on exposure to the air. 



Dust in Factories. — The principle of filtration 

 through cotton wool which Arens used in his 

 method of estimating the amount of dust in the air 

 {ante, p. 151) has been adapted to the prevention 

 of the distribution of dust in factories. The appa- 

 ratus de\ised by Arens and Lamb consists essen- 

 tially of a box with an inlet and outlet. It contains 

 rough moistened flannel, so arranged as to catch the 

 dust carried by the air which passes through. In 

 this way dust is readily prevented from entering a 

 room, and dust in factories from passing into the 

 exterior air. 



Jubilee op M. Berthelot. — This month M. 

 Berthelot, who is seventy-three years of age, cele- 

 brates the fiftieth anniversar}- of his career as a 

 chemist, in which he has attained a world-wide 

 rejiutation. particularly by his brilliant researches 

 on the phenomena of explosion. A plate designed 

 by M. Chaplin will be presented to M. Bertlielot 

 by the other members of the Institute of France to 

 commemorate the occasion. This plate has a pro- 

 file portrait of the distinguished chemist on one 

 side, and on the other a design representing him 

 in his laboratory illuminated by Truth holding a 

 torch, while France presents to him a crown and 

 waves a flag above his head. It will be remem- 

 bered that M. Berthelot has also taken a prominent 

 part in poUtics. and that for some time he was 

 Secretary for Foreign Aft'airs in France. 



Thermal Death-Points op Bacteria. — 

 Different species of bacteria vary greatly in their 

 powers of resisting the action of heat. Speaking 

 generally, pathogenic micro-organisms perish at a 

 much lower temperature than non-pathogenic 

 bacteria. TIius the well-known B. prodiffiosi/s, 

 which forms a beautiful blood-red colony when 

 grown on moist bread, cannot withstand a tempera- 

 ture of 58° C. for more than ten minutes, whereas 

 the tetanus bacillus onh' perishes after six hours 

 at 80^ C. The bacillus of tuberculosis is rapidly 

 destroyed in cultivations at 70° to 80° C. ; but, 

 according to Welch, it can resist in the dry state a 

 temperature of 100° C. for three hours. In milk 

 it has been found to perish after four horns at 

 55° C. ; one hour. at 60° C. ; fi\e minutes, at 80° C. ; 

 and one minute, at 95° C. (Forster). The spores of 

 bacteria can withstand far liigher temperatures 

 than the bacteria themselves. Thus the spores of 

 the tetanus and anthrax bacilli are both extremely 

 resistant to heat, though the latter are destroyed by 

 moist heat at 90° to 95° C. This fact is recognised 

 in the sterilisation of food products, which are 

 first heated to a sufticient temperature to destroy 

 the parent bacteria, then left for the spores to 

 develop, and again heatecl to kill the newl}'- 

 formed bacteria. As regards the action of heat 

 upon the toxic products of dift'erent bacteria, it has 

 been found that some, like the toxin of tetanus, 

 are decomposed and rendered harmless after a 

 short exposure to a comparatively low temperature ; 

 whilst others, like the tosine of anthrax, are only 

 weakened and not destroyed at the temperature of 

 boiling water. 



