RICKETS 325 



Not protective Protective 



Bread Whole Milk (500 cc. per day) 



Oatmeal Cod liver oil 



Rice Butter 



Skim-milk Lard 



Yeast (10-20 grams per day) Olive oil 



Orange juice (5 cc. per day) Arachis oil 



Linseed oil Suet 



Babassu oil Cottonseed oil 



Hydrogenated fat Meat 



Ca 2 (P O 4 ) 3 Meat extracts 

 NaCl 

 Milk protein 



At the time of Mellanby's first publication, the view was largely 

 held that vegetable oils and fats contain no vitamine A and con- 

 sequently the above table was not so significant as is now the case. 

 In spite of some differences, hard to explain, Mellanby is of the 

 opinion that vitamine A is identical with the antirachitic vitamine. 

 According to his findings, the requirements for this vitamine are 

 particularly large when growth is most rapid. In a later communica- 

 tion, Mellanby (1130) stated that the requirement for vitamine A 

 depends very much upon the composition of the diet. The high 

 protein content of a diet stimulates the total metabolism; the children 

 are active and, therefore, require less of this vitamine. On a carbo- 

 hydrate diet, the metabolism is sluggish and the organism requires 

 more of this vitamine. However, it seems more logical to regard the 

 action of protein as "vitamine sparing," judging by our personal 

 experience. Besides the composition of the diet, age also plays a big 

 part, according to Mellanby (1131). Rickets is produced in older 

 dogs only with great difficulty, and spontaneous cures often occur. 

 That this is not quite in accord with human pathology is evident in 

 rachitis tarda and osteomalacia. Therefore, the chapter on the 

 etiology of rickets can not, as yet, be regarded as closed. In spite of 

 the fruitful investigations of Mellanby, several points are not yet 

 clear, for example, the prophylactic influence of meat extracts. It is 

 not impossible that Mellanby's experiments have been rendered 

 somewhat obscure through the non-observance of the light factor 

 which will have to be considered in all future research on this subject. 



Recently, Noel Paton and Watson (1131a) have subjected the 

 researches of Mellanby on young dogs to experimental testing and 



