March. 1918 C. U. C. P. ALUMNI JOURNAL 41 



Zinc Perhydrates 



The production of zinc perhydrates (hydroperoxides) is described by F. W. 

 Sjostrom, in Z. anorg. Cliem., 1917,100, and/. Chem.Soc, 1917, 112, as follows: 

 If to an excess of a solution of sodium hydroxide containing- hydrogen peroxide, 

 a solution of zinc sulphate is added, a total precipitation of the zinc in the form 

 of hydroperoxide is noted. It is difficult however to determine the exact quantity 

 of hydrogen peroxide used, volumetrically, because of the rapid decomposition it 

 undergoes in alkaline solution. Sjostrom, in order to make a more extensive 

 study of the subject, used the following method for the preparation of zinc per- 

 hydrate : The calculated quantity of 30 per cent, hydrogen peroxide was allowed 

 to remain in contact with freshly calcined zinc oxide for a period of several hours, 

 at — 10° C. The product obtained represented a paste-like mass above 2° C. 

 When dried over soda-lime, on a porous plate, at 35° to 40° C, the product was 

 obtained in the form of a white powder. In the white powder the quantity of 

 active oxygen, water and zinc oxide were determined. Oxygen was found 

 present in amount of 8.04 per cent., corresponding very nearly to the formula 

 ZujO (OH) O.OH. At ordinary temperatures the white substance was fairly 

 stable when treated with water, alcohol or ether. Double normal solution of so- 

 dium hydroxide decomposed the compound only slowly. The investigation, how- 

 ever, seems to demonstrate that the product is not a simple chemical compound, 

 as when triturated with water, fractions which contain varying amounts of oxy- 

 gen are obtained. Experiments with this preparation in the same manner, but 

 before drying, yielded three fractions, containing each approximately 12 per cent, 

 of oxygen, but no definite chemical formula could be ascribed. ' Products of a like 

 composition w^ere obtained upon boiling zinc carbonate with an excess of 30 per 

 cent, hydrogen peroxide. The author concludes that zinc perhydrate is a mixture 

 of chemical compounds. 



Toxicity of Cottonseed Products 



F. E. Carruth, Journ. Biol. Chem., 19 17, 32, describes a method for deter- 

 mining the approximate toxicity of cottonseed products. It is known that raw 

 cottonseed possesses highly toxic properties if fed to animals. The presence of 

 about 0.0 per cent, of a plant pigment, gossypol (phenolic in type) is responsible 

 for such action. It is also found that cottonseed meal, obtained by subjecting the 

 seed to hot expression, does not possess this toxic property to so high a degree. 

 This is no doubt due to the fact that gossypol is oxidized into less toxic products 

 during the process of hot expression. When treated with solution of alcoholic 

 potassa, these oxidized products yield a blue color. These oxidation products are 

 insoluble in oil and ether. When the cottonseed is subjected to cold expression, 

 most of the gossypol is removed together with the oil, from which it is however 

 later on destroyed in the process of refining. The presence of unchanged gos- 

 sypol in the cottonseed meal is readily detected by the deep red color it forms in 



