A STUDY IN MORBID AND NORMAL PHYSIOLOGY. 2:^7 



I am acquainted is that contained in tiie Rqmis of (he M»Jlcal Officers of ihe Pririj 

 Council and Local GoKernvuat Boan/, New Series, No. VI., London, Iblo. It is 

 by Prof. Burdon Sanderson, and I sliall quote it in full. 



"Heut stands on tlie same line with carbonic acid, urea, and wafer, as a part of cliomical Work 

 done in the living body. To determine wliellier or not its production is increa.':ed or diminislied' 

 we have to proceed by continuous measurement just as in the other eases, with this difference, that 

 the measurement of heat is a ninch more complicated and difficult proljlem than that of any of the 

 chemical products of lile. Tliere are two methods by which it may Ije atlempied. The lirst con- 

 sists in estimating the thermogenesis from what is known as to the quantity ami 'heat valiu'' of the 

 material daily and hourly consumed in the body, under the conditions to l)e investigated- the second 

 in directly measuring the quantity of heat daily or hourly discharged from the body, this (|Uaiititv 

 being, if the temperature is constant, identical with the quantity i)roduced. In employing the lir.-"t 

 plan, that of estimation, we deiiend entirely on certain experiments made aljont eight vcars a-^o at 

 the Royal Institution, by Prof. Frankland (the accuracy of which has been generally admitted), by 

 which the 'heat value' of the 'immediate principles' of food (albumin, fat and some carbonic 

 hydrates), i. e., the quantity of heat yielded by each in complete or partial o.xidation, was estimated. 



"Of the values oljtained, the most imjiortaiit and the most fret[uently used are those relalinn- to 

 albumin and its product urea, and to fat. A gramme of albumin, according to Frankland, vielils 

 4.998 kilogranniie-uiiits of heat in complete comlnistion, i. e., 4.998 tiuu'S as much heat as is required 

 to raise a kilogramme of water one degree [('.] of temperature. A i;ramme of urea yields :2.20(1 kilo- 

 gramme-units; a gramme of fat 9.009 k. -units. In the disintegration of albumin in the living body, 

 it does not yield the ultimate products (water, ammonia, and carbonic acid) but nearly the whole of 

 its nitrogen passes ont in the form of urea. Consequently in estimating the cpiantily of heat gene- 

 rated by it in the organism (its 'physiological heat value'), we deduct from its total heat value, the 

 heat value of the weight of urea which is derived from it. Now, each gramme of albumin yields 

 one-third of a gramme of urea, that being the quantity which woidd be jiroduced by it if all its 

 nitrogen were, in passing out of the body, to enter into the constitution of urea, for whereas albumin 

 contains 15.5 per cent, of nitrogen, urea contains 46. GG per cent., and ^'.^aui = i- Hence of the 

 total heat value of every gramme of all)nmin consumed physiologically, as much as Iielongs to one- 

 third of a gramme of urea (i. e., '^-_^^ — 0.T35 k.-unit.s) is lost to the organism. Deducting this 

 from 4.998, we have 4.2G3 as the 'physiological heat value' of alliumiii. 



" Leyden found, as has been already seen, that Iris fever patients exhaled during the remission, i. e., 

 when free from fever, 83.8 litres (at 0' C". and 7«0 mm.) of air in 1.5 nunutes, which contained 3.3 

 per cent., i. e., 2.79 litres of carlionic acid. A litre of carboinc acid weighs 1.9712 gramme. Con- 

 sequently the discharge of carbonic acid per 15 minutes was 5.5 grammes or 22 grammes per hour. 

 This gives 528 grammes as the discharge per day. In fever the .same patients exhaled i;34.fi litres 

 in 15 minutes, containing 3.0GG per cent, of carbonic acid, or, 4.127 litres. This gives 32.5 grauniies 

 per hour, or 780 grammes in 24 hours, supjiosing the rate of discharge to be constant. Senator, 

 from determinations made in cases strictly comparable with those of Leyden, estimated the daily 

 discharge of urea in patients on fever diet, but free from fever, as 17.5 grammes. We nuiy therefore 

 take 17.5 grammes of urea (representing 52.5 grammes of albumin), and 52.S grammes of carbonic 

 acid as an approximation as near as can be attained to the true estimate of the discharge of a healihy 

 male person on fever diet. 



"On these data we may proceed as f(d!ows: The physiological heat value of 52 5 grammes of 

 albumin is 220.0 k.-units.' The 52.5 grammes contain 27.82 grammes (53 per cent.) of carb,m, of 

 which 3.5 take the form of urea in order to leave the organism (for uiva contains one-lifth ol its 

 weight of carbon, and 17.5 grammes are discharged). Deducting the remaimler of carbon (/. e., the 

 quantity not so dischars-ed) from 144 grammes (the quantity of earlion contained in ;j28 grammes of 

 carbonic acid) we have IIO.C.S grammes as the quantity of carbon to be aeconnted for as derived 

 from other sources. Now in inanition or on fever diet there is but one non-nitrogenous source of 

 carbonic acid which we have to consider, nnnnly, the fat of the ti.-sues, eonse.iuently it is from fat 

 that the 119.7 grammes of carI,on must be derived. Taking the perecmtag.' ot <-arbou in fat as , (, .-), 

 we have 15G.4 srammes as the weight <.f fat, which must have been consumed .n order to produce 



