August 18, 1911] 



SCIENCE 



223 



employed, which should best contain also five per 

 cent, of rochelle salt. This process has the great 

 advantage that in the conversion of the creatin 

 less pigment is produced than in former methods. 



The Determination of Calcium in the Presence of 

 Phosphates and Magnesium : ¥. H. McCrudden. 

 Methods of Estimating Moisture in Tissues: 

 Waldemae Koch. 



With valuable biological material it is some- 

 times desirable to make vpater estimations and the 

 estimations of the other constituents on the same 

 sample. As there is danger of decomposing the 

 constituents by the high temperature employed 

 for drying in the official method, comparisons of 

 this method with the one devised some years ago" 

 and used in this laboratory were made and are 

 recorded in the following table: 



w. 8 w. 21 



Direct with Dried by Heat 



Alcohol at 95° C. 



Proteins 48.5 47.5 



Phosphatids 21.6 16.3 



Cerebrosides 8.8 9.4' 



Sulphatids 3.6 4.3° 



Undetermined lipoids . 8.2 11.0* 

 Organic and inorganic 



extractives 9.3 11.6 



100.0 100.1 

 Lip P in per cent, of 



total 62.5 53.6 



The Preparation of Tissue for Toxicological Ex- 

 amination: James P. Atkinson. 

 The finely minced tissue is digested with artifi- 

 cial gastric juice. The solution is filtered and 

 extracted for alkaloids ia the usual way. After 

 this extraction the material is evaporated with 

 nitric acid and then examined for metallic poisons. 

 This method has three advantages: (1) The ex- 

 amination may be completed within three days, 

 (2) less personal attention is required, (3) the 

 tissue is completely broken down and therefore 

 allows a better extraction of the alkaloids than by 

 extracting the minced tissue with acid alcohol. 

 Studies of Water Absorption by Colloids: William 



J. GlES. 



On the Diffusibility of Biological Substances 

 through Mubber: William J. GriEs. 



= W. Koch, The Journal of the American Chem- 

 ical Society, Vol. XXXI., p. 1335. 



'Variation due to difference of age. 



* Increase due to fatty acids from destruction 

 of phosphatids. 



The Aging of Flour and its Effect on Digestion: 

 J. A. Wesenee and Geo. L. Tellee. 



The Occurrence of Lipase in the Fat of the Com- 

 mon Fowl {Gallus domesticus) : M. E. Pen- 

 nington and J. S. Hepbuen. 

 If a chicken be kept hard frozen'or at the tem- 

 perature of the room, or at any temperature be- 

 tween these two extremes, the acidity of the fat 

 increases, as has been shown in previous publica- 

 tions of this laboratory. Since the fat-splitting 

 enzyme, lipase, is found in many plant and animal 

 tissues, this investigation was undertaken to de- 

 termine if lipase be present in the crude fat of 

 chickens. The technique is fairly simple. The 

 crude abdominal fat is passed several times 

 through a meat chopper; and its acidity is deter- 

 mined. A weighed sample of the ground fat is 

 triturated in a mortar with sand, and then ex- 

 tracted with ten times its weight of water. Fifty 

 c.c. of the aqueous extract and 1 e.e. of an ester 

 (ethyl acetate, butyrate or benzoate, or amyl 

 salicylate) are mixed, the solution is made neu- 

 tral to phenolphthalein and incubated at 40° C. 

 for periods of time varying between 24 and 168 

 hours — usually 72 hours. Toluol is used as a bac- 

 tericide. Fifty c.c. samples of the aqueous extract 

 are boiled, then run as blank experiments in ex- 

 actly the same manner as were the determinations 

 proper. At the end of the incubation both deter- 

 minations and blank experiments are titrated; the 

 increase in acidity of the determination proper 

 over the blank is due to the action of lipase. 



This research has demonstrated the presence of 

 lipase in the crude abdominal fat of fresh chickens 

 retaining the animal heat, and of chickens kept 

 at temperatures from that of the room to that of 

 the "freezer" for varying periods of time. The 

 highest acidity of the crude fat, and the greatest 

 activity of the lipase, occurred in chickens which 

 had been kept hard frozen for sixteen months, or 

 which had been permitted to putrefy at room 

 temperature. The lowest acidity of the crude fat 

 and the least activity of the lipase were found in 

 a fresh chicken stUl retaining the animal heat. 

 Apparently in fresh birds the enzyme is present 

 as a zymogen, which is converted into the active 

 form as the chicken ages after death. 

 Deterioration in Eggs as shown by Changes in the 

 Moisture Content: A. D. Geeenlee. 

 Eggs contain a high percentage of moisture 

 when fresh — white about 88 per cent, and yolk 

 about 48 per cent. This percentage of moisture 

 is constantly changing, due both to a loss to the 



