244 OF FOOD AND THE DIGESTIVE PROCESS. 



as diseases of the biliary and urinary organs, are really, in a large pro- 

 portion of cases, nothing else than disordered actions of those organs, 

 occasioned by the irregular mode in which the products of decomposition 

 are formed within the blood, and dependent upon some error in diet, 

 either as regards quantity or quality. Thus the "lithicacid diathesis," 

 in which there is an undue proportion of that substance in the urine, 

 and of which Gout is a particular manifestation, is due, not to disorder 

 of the kidney, but to an undue production of lithic acid in the blood ; 

 so long as the excreting action of the kidney is sufficient to prevent its 

 accumulation in the blood, so long the general health is but little affect- 

 ed ; but whenever that action receives a check, various constitutional 

 symptoms indicate that the system is disturbed by the presence of this 

 product of decomposition. And though our remedies may be rightly 

 directed, in part, to facilitating its escape through the kidneys, yet the 

 radical cure is to be sought only in the regulation of the diet, and in the 

 prevention of the first production of the substance in question. Similar 

 remarks might probably be applied to the disorders of the Liver ; but 

 we are, from various causes, far less perfectly acquainted with their 

 character than we are with those of the Kidney. 



423. There is only one tissue, the increase of which is directly pro- 

 duced by an over-supply of food. This is the Adipose or fatty. It is 

 formed almost entirely at the expense of the non-azotized constituents 

 of the food ( 430) ; the walls of the cells, into which the fatty matter 

 is secreted, being the only part of this tissue that is derived from the 

 proteine-compounds of the blood. The production of the adipose tissue 

 is most directly favoured by the presence of a large amount of fatty 

 matter in the food ; but it may also be effected, as will be presently 

 shown, by the conversion of starchy and saccharine substances into fatty 

 compounds. It cannot occur, unless there be in the food a larger pro- 

 portion of substances than can be thus appropriated, than is sufficient 

 to maintain the heat of the system by the respiratory process. Conse- 

 quently, whatever increases the demand for heat is unfavourable to the 

 deposition of fat ; and vice versd. The fattening of animals is now 

 brought to a regular system ; and experience has shown that rest and 

 a warm temperature, with food containing a large amount of oily mat- 

 ter, are most conducive to the accumulation. Kest acts by keeping the 

 respiration at a low standard ; for it will hereafter be shown (CHAP. 

 viii.), that a much larger proportion of carbonic acid is thrown off when 

 the body is in active movement than when it is in repose. External 

 warmth has the same effect ; the demand upon the calorifying power 

 being diminished, and more of the combustible material being left, to be 

 stored up as fat. 



424. The deposition of fat affords a supply of combustible matter, 

 against the time when it may be needed ; and it is consequently found, 

 that the duration of life in warm-blooded animals, when .they are com- 

 pletely deprived of food, is in a great degree proportional to the amount 

 of fat they have previously accumulated. There is no sufficient reason 

 to believe that fatty matter can be converted, within the animal body, 

 into a proteine-compound, which can serve for the nutrition of the mus- 

 cular and other tissues. But the greatest and most constant waste, 



