No abstract

Some people keep in good health, appear to have a good appetite and yet remain very thin. This is a commonplace observation. Their friends may wonder what they do with the food they eat. Yet no physiological abnormality has been demonstrated in such people. Grafe (Grafe & Graham, 1911;Grafe, 1933) has indeed suggested that some people possess a mechanism that burns off any excess of food eaten. This luxus Konsumption mechanism might be set too high, and so might keep a person permanently thin. His experiments on both animals and patients are not generally accepted as reliable evidence for his thesis. In particular he failed to appreciate that starvation per se lowers the basal metabolic rate. Gulick (1922) in careful experiments on himself, a lean person, found that on a high caloric diet and a standard rigime, he gained weight more rapidly when his initial weight was lower than usual than from a start well above his usual weight. These observations were consistent with a luxus Konsumption mechanism, but as he did not control accurately his energy expenditure, they provide no conclusive evidence. We know of no other scientific evidence to support the hypothesis. Newburgh (1950) has shown how tenuous is the support for a luxus Konsumption and himself produced evidence that there is no metabolic control by direct, oxidation of a dietary excess of food.

SCHOPFER [1935, 1] has described a method for estimating small amounts of vitamin B1 by means of its growth-promoting activity on a mould, Phycomyces Blakesleeanus. It has been found that this method, with some modifications, can be used as a comparatively simple test for vitamin B1 in small samples of blood. The method as modified for this purpose is here described. In the discussion that follows the quantitative validity of this test is considered. METHOD The medium. A series of 50 ml. conical flasks is prepared. Into each are measured 6 ml. of a medium composed of an aqueous solution of dextrose, asparagine and salt mixture, of such strength that when the final volume of medium is made up to 10 ml. the concentrations of reagents will be Cone. Dextrose 10 % (A.R.