AGRICULTURAL CHEMISTRY — AGROTECHNY. 311 



Chem., 3 (1911), No. 10, pp. 7////-77,7).— The acidity of 46 out of 5S samples of 

 canne<l tomatoes fluctuated between 50 cc. and 70 cc. of decinormal sodium 

 liydroxid for 100 cc. of juice, and with an average of 59.7 cc. The average 

 specific gravity of the juice from these 46 cans, strained through a cheese cloth 

 of 40 threads to the inch, was 1.0202 at room temperature. The amount of 

 water in the entire 58 samples varied from 90.44 to 96.18 per cent, and of the 

 46 samples was 93.95 per cent. 



On the basis of the above figures the author evolved methods for determining 

 the water in canned tomatoes and the detection of added water. For ascer- 

 taining the former the acidity of 100 cc. of juice, expressed in cubic centimeters 

 of decinormal sodium hydroxid solution, is obtained. This figure is divided by 

 0.1 plus the specific gravity of the juice strained through clieesecloth, and the 

 result (which is termed the ratio) subtracted from the acidity figure. The re- 

 mainder is then taken from 100. In other words, 100 per cent minus the acidity, 

 minus the ratio, equals the percentage of water. 



The excess of water or added water in canned tomatoes is found by subtract- 

 ing from the percentage of water found 90.44 per cent (the average pei-centage of 

 water in canned tomatoes of the proper acidity). The highest amount of water 

 added was found to be a little over 5 per cent. The excess water in the toma- 

 toes was due to the addition of brine, used by some factories for conserving 

 the tomatoes previous to canning. The average amount of salt in canned 

 tomatoes was 0.14 per cent. 



The above formulas can not be employed for cold packed tomatoes. 



Osmotic activity in the egg of the common fowl, A. I). Grei:nlee (Jour. 

 Amer. Chem. Soc, SJf (1912), No. I,, pp. 539-5 Ji5). — As a result of examining 

 White Leghorn eggs at various periods during storage, and at temperatures 

 varying from 32 to 80° F., it was found that the decrease in moisture in the 

 white of the egg was not entirely due to evaporation by the external atmosphere. 

 A certain portion of this moisture seemed to be transferred to the yolk, and this 

 may be explained by the simple process of osmosis. 



"The yolk, which contains a very high percentage of solids, is surrounded 

 by a membraneous tissue called the vitellin membrane, which in turn is sur- 

 rounded by the egg white, a liquid much more dilute than the yolk. By osmosis 

 the water passes through the membrane from the more dilute to the more con- 

 centrated solution until an equilibrium is obtained. In the egg this process 

 continues until the vitellin membrane becomes so weak that it breaks, when 

 the white and yolk begin to lose their identity. This action proceeds with such 

 definiteness that by a process of calculation, knowing the original weight of the 

 egg, the loss in moisture to the external atmosphere can be calculated with 

 surprising closeness to the actual loss as shown by the balance." 



As the change in water content increases its rate with the temperature, and 

 diminishes with the time, it is possible by means of a rate formula which is 

 given to predict the condition of the eggs at any temperature and at a given 

 time within a reasonable storage period. Therefore, " the rate multiplied by 

 the time gives the loss in weight, from which data it is a simple matter to 

 find the percentage of moisture remaining." 



The value of the guaiac tincture test for differentiating raw from boiled 

 milk, RiEVEL (Dcut. Tierarztl. Wchnschr., 20 (1912), No. 11, pp. 161, 162; Molk. 

 Ztg. Berlin, 22 (1912), No. 13, pp. U6, 147).— Tewes' statements (E. S. R., 27, 

 p. 13) in regard to the reliability of this test are not deemed valid under ordi- 

 nary conditions. The chief reason for obtaining a positive reaction with some 

 milks is that they have not been properly pasteurized or boiled. 



Better cream through grading. — A new butter moisture test, G. H. Benken- 

 DOKF (Wisconsin Sta. Bui. 220, pp. U, fiffs. 2).— In this bulletin the advantages 



