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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    brought to light the aetiology of scurvy in man and placed that disease on a definite scientific basis. There was, therefore, reasonable certainty that, if the conditions under which an experimental animal develops rickets could be found, the problem would then be fairly accurately defined and made easier. Fortunately the experimental animal was ready to hand, for it has long been recognized that puppies develop rickets. What to do with the puppies in order to produce the disease was unknown to me, because all the hypotheses that have been advanced to explain rickets in children could likewise be offered in explanation of a similar disease in puppies. At the beginning of this investigation a hypothesis discussed by clinicians was that depending upon the work of Findlay (13) in which he showed that confined puppies developed rickets while other puppies living on the same diet, when allowed exercise, remained normal. According to Findlay the disease of rickets in children could be explained by deficiency of exercise. Experiments, which will be described later in the paper, were prepared in order to test the exercise hypothesis. It was soon evident that, although exercise might be a factor of importance, yet it could not be the primary factor responsible for the disease. It was shown, for instance, that puppies could be confined under very close conditions and yet, if well fed during this period, the disease did not develop. Exp. 198, Figs. 89 and 90; Exp. 350, Fig. 113. In order to get a line for research a large number of preliminary experiments were carried out with the object of testing various hypotheses, experiments many of which gave no result worth following up. It seemed for instance that reduced oxidation changes in the animal’s body might play an important part in the development of the disease. On this basis attempts were made to produce loeafl changes in bones as seen in rickets by, for instance, removing or tying the lymphatic vessels of one limb. It was thought that a local operation of this sort which would interfere with the removal of waste products from the limb, might at the same time reduce the oxidation changes in this way. All the experiments performed on these lines were negative in their results. In other experiments performed with the same object the attempt was made to produce lymphatic stasis more or less complete through¬ out the body by tying the thoracic duct just as it enters the venous circulation. In these experiments no rachitic changes resulted that could definitely be ascribed to the cessation of lymph flow. Again, in order to reduce processes of oxidation, quinine was given to other puppies. These experiments also led to no positive results. During the course of the above-mentioned work, experiments of a tentative nature were being carried out to see how the disease could be effected by diet. In the first experiment made, a puppy was fed on boiled horse flesh without fat. After about ten weeks of this diet the animal developed a rickety appearance. It seemed certain, however, from the general condition of the animal that scurvy was associated with rickets. There was, for instance, obvious pain in walking. After being anaesthetized, the diagnosis of scurvy
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