I2 8 SCIENCE PROGRESS 



are liable to be cut off, such processes may become of paramount 

 importance. Examined in this light, the patents recently taken 

 out by German firms for the synthesis of acetic acid from 

 acetylene (/. Soc. Chem. Ind. 1914, 33, 830) and from acetic 

 aldehyde {loc. cit.) acquire a special interest. Thus it is claimed 

 that if acetylene is passed into a mixture of 250 parts of 30 per 

 cent, sulphuric acid with 100 parts of 95 per cent, ammonium 

 persulphate and 5 to 10 parts of mercuric oxide at 30 to 40 C. 

 from 24 to 25 parts of acetic acid are obtained. A similar 

 change may be effected by anodic oxidation of acetylene if 

 this gas is conducted into the anodic compartment of an 

 electrolytic cell filled with 30 per cent, sulphuric acid con- 

 taining 1 to 2 per cent, of mercuric oxide. On the other hand 

 the oxidation of acetic aldehyde to acetic acid is found to be 

 catalytically accelerated by manganese acetate ; thus a current 

 of dry oxygen passed into 300 kilos of pure acetic aldehyde 

 containing 2 kilos of manganese acetate is absorbed so ener- 

 getically that external cooling has to be applied. According 

 to yet another patent {loc. cit. p. 961) acetic acid may be obtained 

 in a yield of 95 per cent, of the theoretical by passing oxygen 

 under pressure of about 2 atmospheres into acetic aldehyde 

 containing 1 per cent, of eerie oxide, and cooling the mixture 

 when the temperature has risen to 50 to 6o°. 



An investigation of some topical interest is one by Wilcox l 

 upon the physiological effect of tetrachlorethane or acetylene 

 tetrachloride, one of those highly chlorinated compounds 

 which are less familiar to the scientific chemist than to the 

 works chemist. This substance, which is also known by the 

 trade name of Cellon, forms, owing to its solvent action on 

 cellulose acetate, an important constituent of " dope " used for 

 coating the wings of aeroplanes. During last September and 

 October a number of workmen engaged in the manufacture 

 of aeroplanes were taken ill with various symptoms of general 

 malaise and drowsiness, followed by more or less severe toxic 

 jaundice. This condition has been proved from experiments on 

 animals to be due to tetrachlorethane, which is a powerful 

 poison to the liver and kidneys; the Home Office have now 

 laid down regulations for ensuring the proper ventilation of 

 the workrooms and the efficient removal of the toxic vapours. 

 At a time when so much is being said and written about the 

 1 A paper read before the Medical Society of London, March 1, 191 5. 



