Experimental rickets : the effect of cereals and their interaction with other factors of diet and environment in producing rickets / by Edward Mellanby.

  • Edward Mellanby
Date:
1925
Catalogue details

Licence: In copyright

Credit: Experimental rickets : the effect of cereals and their interaction with other factors of diet and environment in producing rickets / by Edward Mellanby. Source: Wellcome Collection.

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    weight according to the amount of oatmeal in the diet are given in Fig. 80. It will be seen that 713 and 717 (2x oatmeal) put on weight more rapidly than 712 and /14 (x oatmeal). Two other series of experiments dealing with the question of interaction between light radiations, diet, and bone-calcification were carried out, but will not be referred to in detail here. In one set of puppies the experimental methods were similar to those already described, but the worst diets were even more unbalanced ^han in 713 and 717 described above. In this series the separated milk in the diet amounted to 150 c.cms. as compared with the 250 to 300 c.cms. taken by 713 and 717. Exposure to the mercury-vapour lamp greatly improved the bone-calcification and general condition when the cereal in the diet was kept small, but with much oatmeal eaten exposure to the rays brought about no improvement. In a third series the control animals were kept indoors and the others were exposed to the sunshine in the open. These experiments were carried out in May and June, 1922, when there was a good supply of sunlight. In addition to the sunlight the exposed puppies had other advantages, for they had more opportunity for exercise, more fresh air, and a different temperature. The results, howevei, were in general similar to those obtained with the mercury- vapoui lamp. When the oatmeal was kept small the exposed animal was much more active and had better calcified bones than the correspond¬ ing animal indoors, but, with a large intake of oatmeal, when the diets were also deficient in anti-rachitic vitamin, the sunlight and other factors brought about no detectable improvement. It is evident that the more oatmeal in the diets above ^ described the worse is the rickets produced and the less effective is the exposure to the mercury-vapour lamp; also that just as there is an antagonism between cereal and anti-rachitic vitamin in the food so far as rickets and general nutrition is concerned, so there is an antagonism between the rickets-producing substance of cereals and exposure of the animals to ultra-violet radiations. B. Exposure of Oatmeal to Ultra-Violet Radiations. It has been found recently by Steenbock and Black [45] and also by Hess [46] that exposure of certain foodstuffs devoid of fat- soluble vitamins to ultra-violet radiations confers upon these substances nutritive properties similar in many respects to those of the absent vitamins. Thus a s}^nthetic diet, perfect so far as is known except for a deficiency of growth-promoting and anti¬ rachitic fat-soluble vitamins, acts temporarily after exposure to ultra-violet radiations as if containing these specific substances. In fact it seems to matter but little whether the radiations are applied to the skin of the experimental animal (rat) or to the vitamin- deficient food eaten by the animal. Even irradiation of the sawdust, used as bedding in cages in¬ habited by rats eating a diet deficient in fat-soluble vitamins, confers upon these animals powers of growth similar to those possessed by directly irradiated animals eating a similar diet. (Hume and Smith [48].)