ITS QUANTITY OF FAT. 247 



Little importance has generally been attached to the quantity 

 of fat in the serum, and we possess very little positive knowledge 

 regarding the quantitative relations of this substance in different 

 physiological and pathological conditions. In most cases in which 

 a determination of the fat has been attempted, this determination 

 has had reference to the blood collectively, so that we have com- 

 paratively little information regarding its distribution between the 

 blood-cells and the serum. 



It appears from the experiments of Simon, Nasse, Becquerel, 

 and others, that in normal blood-serum the fat ranges from 0'2 to 

 2'22-|f of the solid residue. 



For further information regarding the quantity of fat contained 

 in the blood generally, we must refer to vol. i., p. 249. 



Although it would appear from the experiments of Boussingault, 

 to which we have already referred, that the use of fat (taken as 

 food) does not induce any augmentation of the fat in the blood, 

 yet nutrition is not without influence on this constituent of the 

 circulating fluid ; for during the progress of the digestive process, 

 not only have the chyle and the portal blood been found richer in 

 fat, but sometimes also the serum of the blood generally has been 

 actually observed to be rendered turbid by the presence of this 

 substance (Thomson*). Schmid, moreover, found that the serum 

 of horses that had been recently fed contained almost twice as 

 much fat as that of horses which had been kept fasting. 



A horse on which I was experimenting was fed for three days 

 entirely on starch-balls. Immediately before and after this course 

 of diet I abstracted and analysed the blood from the carotid artery 

 and the jugular vein. The result of this investigation, in reference 

 to the amount of fat, will probably be best shown by the following 

 tabular arrangement. 



The quantity of fat 



Before this food. After this food. 



r , ( From the carotid artery .... 1'996 1'665 



(From the jugular vein 2'924 1'366 



q j From the carotid artery .... 2479 1'465 



IFrom the jugular vein .... 2'984 2*226 



This experiment throws light not merely on the constant 

 difference between arterial and venous blood, but also on the 

 influence of an imperfect nutrition as that of an exclusive starch- 

 diet on the diminution of the fat in the blood. The number 



* Phil. Mag. 3rd Series, Vol. 26, pp. 322 and 418. 



