152 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



Study is being given to this reaction to determine whether or not 

 any sharp difference exists between the blood of healthy hogs and 

 that of hogs affected with cholera. 



SO-CALLED " HOG FLU." 



Considerable study was given to the disease commonly known as 

 " hog flu." Twelve herds were carefully observed and the conclu- 

 sion was reached that this illness is not related to hog cholera in 

 any way, and that from the standpoint of symptoms at least it is 

 different from any disease of hogs which prevailed in the United 

 States prior to 1918. This condition appears to be growing more 

 prevalent. It appears chiefly in the fall, winter, and early spring. 

 The losses from death as a rule are not large, but the loss in con- 

 dition among affected hogs is very marked. A number of different 

 bacteria have been isolated from hogs affected with the disease, but 

 so far no single organism has been shown to be capable of pro- 

 ducing it. Tests thus far made indicate that the disease itself is of 

 low contagiousness and that it is transmitted from sick to healthy 

 pigs only with difficulty. It is planned to make an intensive study 

 of this condition if it appears again during the approaching fall 

 and winter. 



RESEARCH WORK ON MEATS AND MEAT FOOD PRODUCTS. 



Excellent progress was made in the study of the composition, 

 nutritive value, and wholesomeness of edible viscera from meat 

 food animals. The study of the proximate chemical composition of 

 the edible viscera has been completed and the results are being 

 prepared for publication. In the determination of the content of 

 vitamin B, or the antineuritic value, of the same tissue and of vol- 

 untary muscle as w^ell, hog muscle was found to be relatively rich 

 in this vitamin and to compare very favorably in this respect with 

 certain glandular organs recognized as being well supplied with it, 

 namely, the kidney and the liver. Beef and veal were found to have 

 much lower content of vitamins, and lamb occupied an inter- 

 mediate position. The heart, liver, and kidney, respectively, from 

 each of the three classes of animals each had a relatively high 

 vitamin content ; the spleen, thymus, pancreas, and brain had much 

 lower values, while the blood, lungs, and tripe contained very little 

 of the vitamin. On the whole, the edible viscera of the hog ap- 

 peared to be rather richer in vitamin B than the same tissue from 

 other animals. 



The study of the nutritive value of the protein of the various 

 animal tissues has been continued. These tests are being carried on 

 with white rats, which are fed rations containing the dried tissue to 

 be tested as the sole source of protein. At least 12 rats are required 

 to test the value of the protein from a single tissue, and the test 

 covers a period of 90 days, so that this line of investigation is very 

 time consuming. The determination of the nutritive value of the 

 protein from the following tissues has been nearly or quite com- 

 pleted : Ox, hog, and lamb liver ; ox, hog, and lamb lieart ; ox and 

 hog kidney ; ox, hog, and lamb muscle. Experiments are in progress 

 with ox and hog spleen and tripe, hog stomach, ox lungs, and mis- 

 cellaneous tissues. 



