10 DYNAMICS OF LIVING MATTER 



that those tissues which possess most fat, as a rule, also possess most 

 lipase.* The more lipase a cell possesses the quicker it will be able 

 to convert the fatty acid and alcohol, which diffuse or are absorbed 

 into it from the blood, into fat; and hence more fatty acid and alcohol 

 must diffuse into such a cell in the same length of time from the blood 

 than into a cell with less lipase. 



We understand how it happens that in times of abundant fat supply 

 our tissues are able to store up fat, while in times of want fat disappears 

 from them. If the blood receives no fat from the intestine, and if the 

 other sources of fat formation, which we shall mention later, cease, 

 the digestive effect of the lipase in the cells must outweigh its synthet- 

 ical action. 



The experiments of Kastle and Loevenhart were not tried with the 

 fats occurring in the body. A. E. Taylor f has filled this gap by showing 

 that the lipase extracted from the castor bean, which digests fats, is 

 able to produce synthetically the triglyceride of oleic acid. The pro- 

 cess is a very slow one, inasmuch as in six months only 3.5 g. of the 

 fat were formed. Taylor concludes that in the body other agencies 

 than mere enzymes must contribute toward the acceleration of the 

 hydrolytic, as well as the synthetical processes. These conditions 

 are, however, not of a vitalistic character, but may be due to the pres- 

 ence of certain other substances. Thus Hewlett has recently found in 

 Taylor's laboratory that the addition of lecithin to lipase accelerates 

 the hydrolysis of fat considerably. Taylor found also that the lipase 

 from the castor bean cannot synthetize every fat, but only the triglycer- 

 ide of oleic acid. Experiments with palmitic and stearic acid and 

 glycerine as an alcohol gave negative results, as gave also experiments 

 with oleic acid and mannit or dulcit as alcohol. This is in harmony 

 with the theory of intermediary reactions, which will be discussed 

 later. 



It is, however, worth mentioning that fat may be produced in the 

 body from carbohydrates, and that lipase. has, as far as we can tell, 

 nothing to do with this mode of fat formation. The most striking case 

 of such an origin of fat is found in the leaves of the olive tree, which 

 synthetize it from the carbohydrates formed from the CO 2 of the air. 

 The fact that a reduction must form part of the process of the forma- 

 tion of fat from carbohydrates may explain why so often a hypertrophic 

 heart has a tendency to fatty degeneration, inasmuch as the hyper- 

 trophic heart is as a rule an overworking heart, and is thus liable to 

 suffer from lack of oxygen. 



* Loevenhart, Am. Jour. Physiology, Vol. 6, p. 331, 1902. 



t A. E. Taylor, University of California Publications, Pathology, Vol. I, p. 33, 1904. 



