1910] ANIMAL PRODUCTION. 767 



The physiological basis of thirst, W. B. Cannon (Proc. Roy. BOO. [London], 

 Per. B, 90 (1918), No. B 629, pp. 288-301, fig. 1).— The author explains that 

 thirst is due to a relative drying of the mucosa of the mouth and pharynx. In 

 the cases of "true thirst" it results from deficient salivary secretion. The 

 salivary glands require water for their action, and in the presence of a general 

 need for water in the body they fail to maintain the normal amount and quality 

 ol" secretion. The importance of this failure to the mechanism of the water 

 supply of the body, he believes, lies in the strategic position of these glands in 

 relation to a surface which tends to become dry by the passage of air over it. 

 Because of the discomfort which thus arises, the salivary glands become a deli- 

 cate indicator of the bodily demand for fluid. 



Importance of calcium for the nourishment of plants, animals, and man, 

 O. I,oi:\\ iXuliinc. Ztschr. Foist u. Landiv., 16 (1918), No. 9-10, pp. 809-336).— 

 This is a general discussion of the subject, with numerous references to related 

 literature. 



Studies on cholesterol. — IV, Experiments concerning the relation of the 

 diet, the blood cholesterol, and the " lymphoid defense," G. Ludkn (.four. 

 Lab. and Clin. Med., 3 (1917), No. 8, pp. 141-174, figs. 8).— The author has 

 found that both radium and Roentgen rays appear to increase the lymphocyte 

 count and decrease the cholesterol content of the blood. The following investi- 

 gations were undertaken with a view to determining the possibility of activating 

 the "lymphoid defense" by dietetic measures. The author was her own sub- 

 ject. As preliminary steps she determined her individual cholesterol standard 

 and the effect of the digestive process on her cholesterol standard during the 

 usual mixed diet. The cholesterol percentage of the common articles of food 

 used during the experiments was also determined. The effects of Gruner's diet 

 (milk, water, lettuce, toast, and jam), of an exclusive meat diet, and of a 

 vegetable diet on her blood cholesterol and cytology were studied. The influence 

 of an excess of carbohydrate was also observed by means of a diet composed 

 as exclusively as possible of oats. Since no cholesterol appeared to be con- 

 tained in oats it was thought that this diet might at the same time furnish 

 data concerning the synthesis of cholesterol in the body. No conclusive evidence 

 of the latter was found. 



According to the author's data, it was definitely shown that the chemical 

 composition of the blood could be changed by dietetic measures. The vegetable 

 diet decreased the blood cholesterol. It was reduced by one-third in 2 days on 

 Gruner's diet and increased as much in 3 or 4 days by the meat and oatmeal 

 experiments. 



A diet which Increases the blood cholesterol weakens the lymphoid defense, 

 whereas a diet which decreases the blood cholesterol increases the lymphoid 

 defense. In persons predisposed to carcinoma the use of food which increases 

 the blood cholesterol may possibly result in the development of carcinoma. 

 whereas dietetic measures calculated to reduce the blood cholesterol by increas- 

 ing the lymphoid defense may be of value in treating carcinoma. 



ANIMAL PRODUCTION. 



Milk as the sole diet of ruminants, A. C. McCandlish (Iotra Sta. Research 

 Hal. '/S ( 1918), pp. 3-11). — Two bull calves, one a grade Jersey castrated at the 

 age of 22 days and the other a grade Holstein not castrated, were fed on 

 nothing but milk and common salt from the date of their birth until their 

 death, which occurred apparently at the age of about 30 and •jr. weeks, re- 

 spectively. The digestible crude protein and total digestible nutrients con- 



