136 THE VITAMINES 



the animals remained healthy, except during pregnancy and lactation, 

 when the vitamine requirements are greater. Osborne, Wakeman and 

 Ferry (I.e. 102) found very little vitamine B in lean beef, and noted 

 that cooking several times in water removes this substance, leaving 

 only traces. Mackay (393a) and Tozer (393b) did not succeed in 

 producing experimental rickets in cats in the absence of vitamine A. 



Lions 



Bland-Sutton (394) observed rickets in young lions in captivity 

 when they are weaned too soon and fed on raw meat. Apparently, 

 there is a lack of vitamine A, since the animals were cured with milk 

 and cod liver oil. 



Dogs 



Dogs are now frequently used for vitamine studies and therefore 

 we shall devote a little more space to this subject. The dog has 

 become particularly important for experiments on rickets. In the 

 historical section, we have already discussed the metabolism of dogs 

 to some extent. It frequently happened, in these experiments, that 

 the various investigators used a diet poor in vitamine although the 

 purpose of the experiments was aside from the question under con- 

 sideration. For instance, there is the work of Cahn (395) in 1886, 

 who studied the results of chlorine hunger. Cooked meat was 

 used as a food, and Cahn described a number of symptoms of chlorine 

 hunger, among which was blood in the stomach contents, which might 

 perhaps have been due to decreased capillary resistance. Similar 

 experiments were also carried out by Trappe (396) with extracted 

 meat, to study the significance of hydrochloric acid in the stomach. 

 Rosemann (397) too, experimented with the same end in view, as did 

 also Bonniger (398), using a diet of extracted meat. Bonniger 

 observed that the animals refused the food and manifested vomiting, 

 apathy and distress. It was indeed remarkable that these symptoms 

 should have disappeared on the addition of sodium bromide. Pfliiger 

 (399) observed enteritis in dogs fed on sterilized meat, poor in fat. 



A whole series of experiments, which have only historical interest 

 at present, were made by Wolfgang Heubner (400) and his school 

 (Lipschiitz, Durlach) on the significance of phosphorus in dogs. 

 The diet usually used for this purpose consisted of tapioca or white 

 rice, egg-albumin, palmin, cane sugar and salts. Heubner thought 



