282    THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [III, III.

interesting probabilities. Thus with rats it has been found that a deficiency of
calcium in blood causes a large decrease of sugar absorption from the small intes-
tine. The question may now be raised as to the possibility of minerals functioning
as a limiting factor in the carbohydrate utilisation by larger animals. Magee and
Reid ³² have recently found that the addition of 0.2% phosphate increased the
absorption of sugar by 50% in rats. These studies open out interesting fields of
research in the physiology of absorption,

    THE RELATIVE IMPORTANCE OF VITAMINS IN THE FEEDING OF STOCK.

There has been a good deal of confusion regarding the necessity of supplying
vitamins to farm animals. Many results have been ascribed to unknown food
factors which could easily be explained on the basis of their mineral constituents.³³
Thus according to Orr ³⁴ in feeding experiments with fowls, where yeast is used as a
source of vitamin B, some of the beneficial results obtained by giving yeast, can also
be observed by giving a solution of inorganic phosphate and glucose in an amount
equivalent to that obtainable from yeast. It is known that fowls have a high
requirement of phosphorus while yeast is also a good source of phosphorus. The
beneficial rsults of cod liver oil have been attributed to its vitamin content. It
appears that vitamin D may be necessary for stock feeding. Apart however from
its vitamin D content, the value of the oil may be due to its iodine content.
Compared with ordinary feeding stuffs, many of which contain very little iodine, cod
liver oil is rich in this substance and the results obtained by Smith ³⁵ on pigs and
Marine and Kimball³⁶ have shown that the administration of minute quantities of
iodine may be followed by marked beneficial effects. With regard to the necessity
of other vitamins, Theiler and his co-workers ³⁷ in their experiments on cattle, sheep,
goats and horses on rations deficient in vitamins, did not observe any symptoms
which could be ascribed to vitamin deficiency. In the case of sheep, the addition of
vitamin B to the ration led to no improvement in their condition. The lack of
dependance of growing cattle on their rations for vitamin B₁ ³⁸ and B₂ has been
recently explained by the finding ³⁹ that these factors are synthesised by the bacteria
in the rumen of the species. In their experiments on pigs which are rapidly growing
animals and therefore are likely to suffer from vitamin deficiency, Orr and his
collaborators ⁴⁰ could not produce any sign of malnutrition on ration deficient
in vitamin A or C. Similar results have been obtained by Golding and his
co-workers ⁴¹ with vitamins A and D who could not produce rickets in pigs
on vitamin deficient diet although growth was stimulated in pigs of low weights
on supplying pure milk and other substances. It is thus obvious that the require-
ments of the pig for these vitamins must be so low that there is no danger of