1920.] 



Experiments with Dried Blood. 



267 



fed to pigs together with such offal as the " manifolds" or 

 third stomachs of sheep and oxen, where proximity to a 

 slaughterhouse allows purchase in a fresh condition. 



A series of experiments was, therefore, designed to test the 

 value of dried blood as an addition to ordinary carbohydrate 

 diets, and also to ascertain how far it could be used to supple- 

 ment the deficiency of a single foodstui^ unsuitable by itself, 

 either owing to lack of nitrogen or to absence of accessory food 

 factors. 



Feeding Trials. — A number of trials have been carried out by 

 diiierent investigators on dried blood, and the result-s have 

 indicated that it possesses considerable food value when added 

 to a mixed diet, but it was decided to restrict the experiment 

 to the effect of blood as an addition to a carbohydrate diet. 

 For this purpose two series of experiments were arranged : 



(1) Blood as an addition to maize meal. 



(2) Blood as an addition to wheat offals. 



Some experiments on the addition of casein to maize meal 

 are recorded in Amer. Jour. Bio. Chcju. (Vol. xxix., Part 3), 

 maize -r casein + salt mixture and maize + germ being tried 

 against maize + salt mixture only. In these trials three 

 animals in each lot were fed for a period of iSo days, with the 

 following results : — ■ 



I\Iaize 4- casein -f- salt mixture : average gain 1 79 lb. 

 Maize+germ .. .. 119 



Maize + salt mixture only .. ,, 12.31b. 



These results indicate an extraordinarily low value for maize 

 as a single food, and it was thought tliat a basal diet of maize 

 would allow any effects of added blood to be clearly seen. It 

 has also been stated that the addition of blood to an ordinary 

 diet not only caused a greater increase in the live weight of 

 blood-fed pigs than would be expected from its food value, but 

 also that the proportion of the carcass to live weight was 

 greater than that in animals fed in the ordinary way. It was 

 therefore decided to follow the pigs through the slaughterhouse 

 and to ascertain the dead-weight proportion of the animals as 

 well as the gross increase during the course of the experiment. 



Twenty- eight pigs were selected and divided into four lots 

 of seven pigs each, each lot being arranged to average, as nearly 

 as possible, the same total live weight. Each included two 

 " large white," one " large black " and four cross-bred pigs, so 

 that a fair average on such animals as are used in ordinary 

 farming practice could be obtained. 



