Experimental rickets / by Edward Mellanby.

  • Edward Mellanby
Date:
1921
Catalogue details

Licence: In copyright

Credit: Experimental rickets / by Edward Mellanby. Source: Wellcome Collection.

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    was made certain by the haemorrhages present. It was found at this time that if puppies, in addition to the meat, received a substantial quantity of milk each day, they remained in good health. While testing the effect of varying salts in the diet, a mixture consisting of milk and equal parts of oatmeal and rice was used as the basal diet because of its low sodium content. It was found that on a diet of oatmeal, rice, and milk puppies ultimately developed rickets when the milk was limited to about 200 c.c. per diem. The addition of sodium chloride did not influence the development of the condition. The addition, on the other hand, of a small quantity of potassium chloride resulted in severe malnutrition and death. A large number of experiments were made in which this diet of milk, oatmeal, and rice was used as the standard and, in all cases under laboratory conditions, the animals developed rickets. The treatment which prevented the disease was an increase in milk consumption to, say, J litre a day. When the oatmeal and rice were replaced by ordinary white bread, other conditions being the same, rickets also developed. The drawback to the use of this diet was that the period necessary for the production of the disease was long, often 4-6 months, and, except in puppies of a large rapidly-growing type, the bony changes and other symptoms were not as strongly developed as was desirable from an experimental point of view. The natural question that arose at this stage was, what was the factor associated with the large milk intake that prevented the development of rickets ? The answer that suggested itself, as may well be imagined in consequence of the results obtained by Bland Sutton on the effect of cod-liver oil when given to young lions in the Zoo, was that the fat of milk contained some inhibitory factor. It appeared in other words as if the explanation of rickets was to be found in the theory that a deficient fat intake was the main responsible factor. In order to test this point the fat of the milk was removed by skimming, and it was noticed that the animals developed rickets more rapidly. At this stage of the work a concoction called ‘ Maryle- bone cream ’ was being distributed in the Infant Welfare Centres in London as a curative agent for rickets. ‘ Marylebone cream ’ was then an emulsion of linseed oil, and as a matter of interest the effect of linseed oil on the development of the disease was tested. The cream was removed from the milk by skimming and replaced by an equivalent quantity of linseed oil, and it was soon discovered that linseed oil did not possess the anti-rachitic effect as did the milk fat. Before this period McCollum’s (14) work on the distribution of Fat-soluble A vitamine was published. The results of experiments carried out with linseed oil as opposed to butter naturally led to the suggestion that the Fat-soluble A vitamine played some part in the aetiology of the disease. It seemed advisable to investigate the action of the other two vitamines, viz. the water-soluble and the anti-scorbutic, on rickets. In order to test the effect of the water-soluble vitamine, yeast was added to a diet of milk, bread, and linseed oil (in these early experiments 6770 B
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