On the formation of fat in the animal body / by J.B. Lawes and J.H. Gilbert.

  • Lawes, J. B. (John Bennet), 1814-1900.
Date:
1877
Catalogue details

Licence: Public Domain Mark

Credit: On the formation of fat in the animal body / by J.B. Lawes and J.H. Gilbert. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    t It would be necessary to reduce the estimate of the amount of fat stored up by more than 30 per cent, to bring if low enough to be covered by the fat in the food, pliis that deriv- able from the transformed nitrogenous substance, leaving all the other calculations the same. If, however, we were to assume that 100 nitrogenous substance yielded only 51'4 fat, it would be requisite to reduce the estimate of the fat in the increase by more than 40 per cent., to reverse the indication. This is on the assumption that the whole of the fat of the food was stored up in the animal, which would certainly not be the case. It is also on the assumption that the whole of the nitro- genous substance of the food, not stored up as such in the increase, was digested, and available for transformation into fat, &c., but this again is certainly not the case. According to our own experiments, it may be supposed that, with a pig feeding exclusively on good barley-meal, about one-sixth of the total nitrogen veided would be in the faeces. But if it be assumed, according to the estimates of E. Wolff \ that 20 per cent, of the nitrogenous substance, and 32 per cent, of the fat of the barley, would be voided undigested, and therefore without contributing to the deposition of fat, our estimate of the amount of fat stored up in the increase would have to be reduced by more than 55 per cent., or considerably more than half, to bring it within the amount derivable from the resorbed fat, and the transformed nitrogenous substance of the food. It is submitted that a range of erro^r in our estimates, at all approaching even the lowest of those above assumed for the sake of illustration, is simply impossible. It is further sub- mitted, with the utmost confidence, that such is the wide margin in the case of pigs fattening rapidly on their most appropriate fattening food, that the question of whether or not the carbo-hydrates contribute to fat-formation may be conclusively settled by a properly conducted experiment with those animals, without any analysis of the feces or the urine, or any determination of the products of respiration. To this end, we would suggest that two animals be selected, of a breed of good fattening quality, and as nearly as possible alike in characters and in weight. A convenient size and weight would i Landivirthschaftlichc Fiittcrungslehrc, Appendix, Table 1.