24 



SCIENCE 



[N. S. Vol. LIII. No. 1358 



cent, by volume and is usually less. More- 

 over, ■when the cars are re-iced the air in the 

 cars is renewed to some extent and the ac- 

 cumulated carbon dioxide largely swept away. 

 In ventilated refrigerator cars the percentage 

 of carbon dioxide is lower. It may, while the 



TABLE I 



Accumulated Carion Dioxide, Expressed in per 



cent, by Volume, in Refrigerator Cars 



Loaded with Strawberries 



cars are standing after being loaded, become 

 nearly or quite as great as in imventilated 

 cars. When the cars are moved it drops to 

 0.2-0.4 per cent, and rarely exceeds that 

 amount. 



The accumulation of carbon dioxide in un- 

 yentiated refrigerator cars is apparently not 

 sufficient, with strawberries, to cause injury 

 to the berries. 



H. F. Bergman 



Bureau op Plant Industry, 

 Washington, D. C. 



THE AMERICAN CHEMICAL SOCIETY 



{Continued) 

 Tlie preparation and analysis of a cattle food 

 consisting of hydrolysed sawdust: E. C. Shereard 

 and G. W. Blanco. Investigations carried out at 



1 Immediately after re-icing. 



2 Car re-iced seven hours previous. 



the Forest Products Laboratory indicate that a 

 cattle food can be prepared from eastern white 

 pine sawdust and that it has considerable food 

 value. The cattle food was prepared by digesting 

 the sawdust for 15 to 20 minutes with 1.8 per 

 cent, sulphuric acid at a steam pressure of about 

 120 pounds per square inch. After cooking the 

 sugars were extracted with water and the acid 

 removed from the solution by means of lime. The 

 liquor containing the sugar was evaporated to a 

 thick syrup and mixed with the digested residue 

 which had been previously dried. The whole was 

 then dried to a moisture content of 15 per cent. 

 It is shovm that when the product has a greater 

 moisture content than 15 per cent, the keeping 

 qualities are not good. Leaching experiments re- 

 moved all but 2.04 per cent, of the total acid and 

 all but 7.16 per cent, of the total sugar. A com- 

 parative analysis of the wood before and after 

 conversion shows that cold water soluble, hot 

 water soluble and NaOH soluble substances are 

 greatly increased but the ether soluble substances 

 are almost unchanged by the treatment. The pen- 

 toses are reduced 46.4 per cent, while the methyl 

 pentosans are not affected. The total cellulose is 

 reduced by 21.68 per cent. The sugars produced 

 correspond to 71.5 per cent, of the cellulose re- 

 moved by the digestion. The lignin content is 

 unchanged. The crude fiber corresponds to about 

 75 per cent, of that in the original wood. The 

 cellulose is greatly altered by the treatment. Prac- 

 tically the whole of the cellulose obtained is sol- 

 uble in 17.5 per cent, alkali. It is reprecipitated 

 from the alkaline solution by dUutiou with water. 

 After filtering no precipitation of beta-cellulose 

 is obtained upon acidification with strong acetic 

 acid. 



A comparison of wood cellulose and cotton cellu- 

 lose: S. A. Mahood and D. E. Cable. Samples of 

 wood cellulose and cotton cellulose which had been 

 subjected to various conditions of cooking and 

 bleaching were analyzed by determining a number 

 of constants on them, including ash, moisture, 

 alkali solubility, pentosan and methyl pentosan 

 content, methyoxy content, ether extract, cellulose, 

 lignin and "copper number"; for the purpose (1) 

 of following the changes which take place in wood 

 cellulose on successive cooking and bleaching 

 treatment with a view to increasing the yields of 

 purified cellulose by varying these conditions and 

 (2) to determine so far as possible the points of 

 similarity or difference of cellulose from wood and 



