Many forms of injury are known to occur in experimental animals when they are dosed with greatly excessive amounts of oils or concentrates containing vitamin A. Takahashi, Nakamiya, Kawakami & Kitasato (1925) tested the effect of excess of their crude concentrate 'Biosterin' when given orally to rats and mice, and observed loss of hair, emaciation and paralysis of the hind legs. After periods varying from a few days to several weeks the animals died, and at autopsy fatty degeneration of the liver,
IN earlier work [Harris & Leong, 1936; Harris et al. 1938] it was shown that the extent of the body's "reserves" of vitamin B1 might be measured by means of a test on the urine, similar in principle to that previously introduced for vitamin C [Harris et al. 1933; Harris & Ray, 1935]. The urinary output was found to depend on the past intake, being negligible in beri-beri or in "conditioned" deficiencies of vitamin B1 and being lowered in certain other abnormal states.To simplify the procedure, several investigators [e.g.
DURING the past two years a systematic study has been made in this laboratory of the various possible sources of error and the technical difficulties involved in the thiochrome test, based on the now well-known reaction first described by Jansen [1936]. These errors and difficulties are more serious than is generally appreciated. In an earlier paper [Wang & Harris, 1939] a procedure was described for urine, by which-interference from non-specific substances and various other problems of technique were successfully overcome. Our results were controlled by biological tests, and this proof of the reliability of the method applied to urine has been further confirmed since [see accompanying paper, Harris & Wang, 1941]. The present communication describes how the technique used by Wang & Harris mtny be adapted for estimating vitamin B1 in foodstuffs and in animal and plant tissues. As we have again repeatedly checked our results by biological assays, we feel considerable confidence in the method which we are now recommending.
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