L.S. Palmer

The effect of heat on the calcium salts and rennet coagulability of cow's milk.

Summary It is shown that the partial fixation of the calcium salts of milk by pasteurization or boiling is readily explained simply on the grounds of the effect of heat on colloidal solutions of CaHPO4, the calcium phosphate natural to cows milk. It is shown further that the effect of heat in retarding the rennet coagulability of milk is not related directly to the loss of colloidal CaHP04 because the addition of colloidal CaHP04 to dialyzed milk does not restore its coagulation by rennet, while the addition of CaCl2 or HCl does restore this property. The phenomenon of rennet coagulation is discussed briefly from the standpoint of the chemical and physico-chemical reactions involved, and also from the standpoint of the possible bearing which the addition of calcium salts to heated milk has on this phenomenon.

The role of honey in the prevention and cure ofnutritional anemia in rats

Summary Laboratory rats have been fed a diet of raw whole milk supplementedwith 20 per cent of honey. Rats receiving milk to which 16 per cent sucrose was added served as controls. Rats which received a milk-dark honey mixture ad libitum showedan increase in the hemoglobin content of their blood, while the hemoglobin content of rats fed light honey or sucrose supplement in their milk gradually decreased, The gain in weight as well as the food consumption in the first group was also greater. In paired feeding experiments, it was demonstrated that rats receiving a dark honey supplement were able to maintain their hemoglobin at almost the initial level, while the hemoglobin content of rats fed a light honey supplement declined to a level only about 30 per cent of normal, where it remained almost constant. The hemoglobin content of the blood of the control animals receiving a sucrose supplement fell steadily. When the hemoglobin content of the blood of young rats was reduced by a whole milk diet to 6 or 4 Gm. per 100 c.c. level, the addition of 20 per cent dark honey to the milk caused a gradual increase in the hemoglobin, while the addition of 20 per cent light honey permitted a gradual further decline in the hemoglobin until a level of about 3 Gm. per 100 c.c. was reached. It is concluded that the dark honey can play a role in the preventionand cure of nutritional anemia in rats, while light honey is less effective as a source of the blood-forming mineral elements.

Requirement of the flour beetle (Tribolium confusum Duval) for vitamins in the B group.

Insects offer certain possibilities for vitamin assay. If the vitamin requirements of certain insects were known it should be possible to assay vitamins with much less time and labor than with rats or similar animals. A suitable insect for nutritional research is the flour beetle, Tribolium confusum Duval. When raised on whole wheat flour at 32° and 70% humidity, the larvae transform to the pupal stage in an average time of 16 days. Sweetman and Palmer 1 found that on a diet of purified food materials devoid of all vitamins the insects did not pupate. The addition of a small amount of material containing the vitamin B complex enabled the larvae to pupate in a normal time. The renewed interest in methods for assay of the vitamins in B group brought about by the recent advances in the chemistry of these substances prompts us to report briefly experiments conducted by us in 1931-32. In this study an attempt was made to determine which members of the vitamin B complex are necessary for Tribolium. A basal diet of casein 15, crisco 3, Osborne-Mendel salt mixture 4, dextrin to 100 was used. Various vitamin supplements were added to 5 gm. quantities of the basal diet, and the food was placed in a vial with 20 two-hour-old larvae. The vials were kept in a temperature cabinet at 32°C. and 70% humidity and the average time of pupation recorded. A vitamin B1 concentrate prepared from rice polishings was used. The average time required for pupation with the various supplements to the basal diet were: vitamin B1 concentrate equivalent to 50% rice polish no pupation, 5% autoclaved yeast no pupation, 1% autoclaved yeast plus vitamin B1 concentrate equivalent to 2% rice polish 19.2 days. This indicates that Tribolium requires a heat stable factor in addition to vitamin B1. It was found that this heat stable factor was destroyed by autoclaving at pH 13 for 4 hours.

Yeast as a source of vitamine-B for the growth of rats

Yeast is commonly considered the richest source of vitamine-B for the growth of young animals. We have fed groups of rats in colonies on a basal diet of purified casein 18 per cent., salts 3.7 per cent., agar 2 per cent., butter fat 5 per cent., with dextrin to make 100 per cent., and have supplied the vitamine-B in the form of dried yeast of various sources, both as an integral part of the diet or separately in the form of a tablet. Our results were as follows: Air-dried Fleischmanns bakers yeast containing 40 per cent. yeast in the dried product failed to produce normal growth in all cases when the ration contained 4 per cent. or less of the dried product and certain individuals even failed to make normal growth when the dried yeast formed 10 per cent. of the diet. Out of 20 rats, 9 were females, and none of these produced young during the 2 to 4 months of the experiment. When the same yeast was fed separately, 0.6 gram per day per rat was required to secure normal growth. Two out of 4 females on this diet produced young (total of 3 litters) but all the young were destroyed by the mothers. A dried brewers yeast prepared by us from a wet mixture of bottom yeast and wort secured from a local brewery produced only about one-half normal growth when fed as high as 10 per cent. of the diet, but when these rats were transferred to a mixed diet of grains and milk their growth curves rose sharply towards the normal. When the same yeast was fed separately to other rats at the rate of 0.2 and 0.4 gram per day per rat the results were little better than when the yeast was incorporated in the diet at the rate of 10 per cent. There was no reproduction.

Biochemical Properties of the Blood of Pigeons in Polyneuritis and Starvation.

The data in Table 1, showing the analyses of the whole blood of (1) normal pigeons, (2) normal pigeons starved until they had lost 40 per cent. of their body weight, (3) pigeons with “latent” polyneuritis, (4) pigeons with acute polyneuritis, (5) pigeons which had attained normal weight following acute polyneuritis, i.e. “relieved polyneuritis,” and (6) pigeons starved to a 40 per cent. loss of weight following “relieved polyneuritis,” indicate that the decrease in total solids and in the nitrogenous constituents of the blood, both protein and non-protein, as well as the diminution in the erythrocytes, are probably due to the self-imposed starvation which accompanies the later stages of polyneuritis in pigeons. It is to be noted, however, that simple inanition in its advanced stages is accompanied by a decline in the relative amount of protein in the blood which is not apparent even in acute polyneuritis. This result is contrary to the recent observations of Pacchinsa. 2 None of the usual “symptoms” of polyneuritis accompanied simple inanition in these experiments. The polyneuritis diet consisted of a mixture of polished rice, casein, butter fat and salts.