S. M. DAS GUPTA                                 265

winter which has an antagonistic effect on the Reichert-values of the butter-
fats. The results, therefore, clearly demonstrate the effects of carotene
present in the feeding-stuff as against both the stage of lactation of the cow
and cold temperature of the winter which tend to lower the Reichert-values.

It must be admitted, however, that the carotene ingested in the above
experiments was either in the form of grass or red palm oil which also contain
considerable proportions of fatty acids. So the increase in the Reichert
values with the carotene content might as well be due to fatty components
present in grass or red palm-oil. So the idea developed in this paper regarding
the role of carotene in the oxidation of fats is subject to experimental evidences
in its favour from feeding experiments with pure carotene which are in
progress.

                         SUMMARY AND CONCLUSIONS

Effects of feeding paddy straw, grass (Cynodon dactylon) and their mixtures
on the carotene and vitamin-A contents of butter were studied on two cows.
The Reichert and Iodine values were also determined at the same time. The
carotene and vitamin-A contents and the Reichert values were found to increase
on the ingestion of grass which again lowered down on the ingestion of
paddy straw (containing little or no carotene).

A fairly large number of butter-fats (107) prepared during the autumn
and the winter seasons in Vikrampur (a well-known butter producing centre
of Bengal) were assayed for their carotene, vitamin-A, Reichert and Iodine
values. During the autumn (average temperature 86°F), the cows mainly
lived upon paddy straw and during the winter (average temperature 72°F)
the cows were fed on fresh grass, e.g., Kâlaisak, containing on the average
6.6 mg. of carotene per 100 grm. of fresh sâk. It has been found that all the
above values are markedly higher in winter than during autumn inspite of
the cold temperature of the season. The butter from an individual cow which
was on straw during autumn and grass during winter gave similar results
in spite of the adverse effects of the cold temperature and stage of lactation.

Striking results have been found on feeding a cow with red palm oil
when the carotene, vitamin-A and the Reichert value progressively increased
as the dosages of the oil were increased.

All the above experimental results suggest that the lipochrome pigment
carotene may play some part in the production of more volatile fatty acids
in cow's milk fat.

                                   ACKNOWLEDGMENTS

My best thanks are due to Lt.-Col. T. C. Boyd, F.R.C.S., M.R.C.P.I.,
F.I.C., I.M.S., Rai Bahadur Dr. K. N. Bagchi, M.B., D.T.M. (Cal. & L'Pool.),
F.I.C. and Dr. B. Ahmad, Ph.D., for their keen interest taken in my work.