An experimental investigation on rickets : two lectures delivered at the Royal College of Surgeons of England / by Edward Mellanby.

  • Mellanby, Edward, Sir, 1884-1955.
Date:
1919?]
Catalogue details

Licence: In copyright

Credit: An experimental investigation on rickets : two lectures delivered at the Royal College of Surgeons of England / by Edward Mellanby. Source: Wellcome Collection.

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    Using Diet I., we see in Table II. that increasing the whole milk from 175 to 500 c.cm. per diem prevents the development of rickets. In other tables are experimental results obtained by means of Diet II. On Diet II. not only does meat but both the watery and alcoholic (80 per cent.) extracts have an inhibitory effect. (Table III.) On the other hand, the protein residue after loss of extractives allows rickets to develop. Table IV. shows the effect of adding malt extract and yeast to Diet II. Yeast therefore has no protective influence. Malt extract has some inhibitory action and delays the onset of rickets when added to Diet II. A large number of experiments were now made in which the effect of different fats were analysed. A few of the results are given in Table Y. Many other fats and margarines, animal and vegetable, were tested, but almost uniformly they prevented rickets, the only undoubted excep¬ tion being linseed oil. The, results allowed the evolution of Diet III., in which separated milk was used in order .to eliminate the milk fat, whose place was taken by linseed oil. Yeast was also added to the diet. Using this diet, a closer analysis of the effect of different fats was possible. (Table YI.) Now we see from the calcium results, which are an accurate indication in this case of the rachitic picture, that the value of the oils is graded, cod-liver oil being the best and linseed oil the worst; the vegetable oils, olive and arachis, are not so good as butter. It was found that adding orange juice (^ orange per diem) did not prevent rickets. Further, that the addition of 5 g. calcium phosphate, or doubling the separated milk and so increasing the calcium intake in this form was without pre¬ ventive action on the development of the disease. In Diet IV., therefore, the separated milk was doubled and 3 c.cm. orange juice per diem also given. On Diet IV. the growth and general health of the puppies seemed better, and both these factors are of importance in such an investigation. Another improvement was to substitute 5 g. of yeast by a small quantity of a commercial yeast extract (3-4 g. per diem). On Diets III. and IV. it was found that small quantities of meat and meat extract did not prevent rickets developing, as they have previously been observed to do when used in addition to Diet II. Table VII. illustrates some of these results. Although meat did not prevent rickets, a closer analysis of these and other results showed that it did have some inhibitory effect. It will be noticed, for instance, that the CaO present in the fresh femur shaft of Exp. 144, where 50 g. of meat was eaten, is higher than in Exp. 141, where only 5 g. of meat was added to Diet III. The action of small quantities of meat (10 g. per diem) is best seen when given with quantities or types of fat otherwise ineffective in preventing rickets. It will often be seen to keep the growth l