Studies on Enzyme Action. 



187 



18 grin, of a pale yellow oil was thus obtained, which became turbid on 

 standing, slowly clearing again on heating to 30° C. The saponification 

 value of this oil was 183'5, that of the olive oil used being 19T7 ; on 

 acetylation the saponification number was increased to 248 - 7, the "acetyl 

 value " being 78 - 6. These data favour the assumption that the oil contained 

 a high proportion of diolein. It is obvious, however, that no final conclusion 

 is possible until experiments have been made with definite acids and the 

 products have been isolated and characterised. 



In view of our results, we venture to call attention to several directions in 

 which the fats now deserve renewed attention. 



Our knowledge of the manner in which they are absorbed and utilised 

 under vital conditions is at present very vague in character and much of the 

 evidence on which reliance is placed appears to be open to question. It is 

 generally believed that* when ingested, fat is rapidly hydrolysed, under the 

 influence of the pancreatic secretion and that derived from certain tracts of 

 the intestine, this change being regarded as a necessary preliminary to its 

 passage through the walls of the villi prior to entry into the circulatory 

 system. Lipase appears to be widely distributed throughout the organism. 



Apparently, whenever fat is to be transferred across cell membranes, it is 

 hydrolysed : assisted by the emulsifying influence of the biliary fluid, the 

 fatty acid that is liberated during digestion of fatty food can penetrate tissues 

 that are impermeable to the fat but it is held that on entry into the villi the 

 fatty acids are rapidly re-associated with glycerol and pass into the lacteals 

 as fat. In fact, all fat that is stored is supposed to be fat that has been 

 reconstituted from fatty acids. In the normal heart and other tissues, 

 however, the fatty acids are not present as glycerides but apparently are 

 combined in such a way that their histological behaviour is different from that 

 of fats — the discriminative staining agents being without effect in such cases. 



If the vital mechanism be such that only fatty acids can pass through, it 

 is clear that in presence of lipase fats would undergo complete hydrolysis 

 readily, under natural conditions, if the acids were removed as they were 

 liberated, as reversal would be prevented. 



Our observations appear to show that hydrolysis would be most rapid in 

 presence of a minimum amount of water ; they therefore favour the conclusion 

 that conditions which would tend to reduce the concentration of the cell fluid 

 would promote the conservation of fat — a conclusion which is perhaps 

 applicable in explanation of the obesity which apparently is a frequent 

 consequence of the indulgence in large quantities of weak alcoholic fluids 

 such as Lager beer. 



VOL. LXXXVIII. — B. P 



