VITAMIN B (B^) 77 



a short time, after which there was a decrease in rate, more marked the 

 smaller the amount of yeast fed. 



The correlation between the size of the animal and its require- 

 ment of vitamin B was further shown in this and in a later paper (Os- 

 borne and Mendel, 1925) by the growth curves of rats fed varying 

 dosages of the vitamin B concentrate of Osborne and Wakeman. 

 Similar relationships between the vitamin B requirement of an animal 

 and its size and metabolic rate were demonstrated by Pilcher and 

 Sollmann (1925) for pigeons, by Beard (1926) for mice, and by Cow- 

 gill and coworkers for dogs, mice, rats and pigeons. 



The effect of vitamin B upon oxygen consumption and the metab- 

 olism of various food constituents has been studied with variable 

 results. The lowered temperature and difficulties in respiration noted 

 in the final stages of vitamin B deficiency led some investigators to 

 the conclusion that vitamin B is concerned in maintaining the activity 

 of the oxidizing mechanism of the body, and many unsuccessful at- 

 tempts have been made to discover the cause of the alleged lowered 

 consumption of oxygen. Papers from Drummond's laboratory on the 

 physiological role of vitamin B have done much to clear up the con- 

 fusion in the literature and to relate the various phenomena observed 

 in vitamin B deficiency to inanition following failure in appetite. Since 

 these papers contain a critical discussion of the conflicting literature, 

 together with a repetition under carefully controlled conditions of 

 much of the earlier work, they are reviewed somewhat fully here. 



Drummond and Marrian (1926) first attempted to verify the assumption that 

 deprivation of vitamin B leads to a reduction of the oxygen utilization of the 

 animal, by testing the washed and unwashed tissues of normal pigeons and rats, 

 with those of others killed in the final stages of vitamin B deficiency, for their 

 ability to reduce methylene blue according to the method of Thunberg (1918). 

 Contrary to the results reported by W. R. Hess (1921, 1922, 1923), Hess and 

 Messerle (1922), and Rohr (1923) in similar studies, but with the use of 

 m-dinitrobenzene as indicator, the normal and "beriberi" muscles showed no dif- 

 ference in their rate of decoloration of the dyestuff, and hence in their oxidizing 

 mechanism; nor was the reduction in the beriberi muscle hastened by the addition 

 of small quantities of yeast as claimed by Abderhalden and his colleagues. The 

 results obtained by this indirect method were confirmed by the direct method of 

 determining the oxygen uptake of isolated tissue preparations in a respiration 

 apparatus. The uniformity of results with normal and beriberi tissues was in 

 complete disagreement with the findings of Abderhalden and Schmidt (1920) and 

 Shinoda (1924) but in agreement with those of Roche (1925). 



Concluding that the tissues themselves show no appreciable impairment of 

 oxidative activity in vitamin B deficiency, Drummond and Marrian next made a 

 prolonged study of the gaseous metabolism of rats in various states of nutrition, 

 as determined in a closed circuit system with constant temperature control and 

 provided with a recording spirometer. The data obtained on rats during progres- 

 sive vitamin B deprivation indicated that the oxygen consumption remains at a 

 normal level until the final phase of the disturbance which, as has been noted 

 previously, is characterized by a marked loss in weight, rapid fall in body tern- 



