BY JAMES M. PETRIE. 807 



sidered that these reactions represent the simplest form in which 

 carbohydrates are converted into fats. True it is that only the 

 lower acids (to caproic, C 6 ) were obtained in the above way, 

 but, as Leathes puts it, the formation of even caproic acid from 

 lactic acid must involve just such a synthesis as that which 

 occurs in plants and animals, which if continued must lead to 

 the higher members of the series. 



From seeds Stoklasa(14) has isolated an enzyme which produces 

 alcoholic fermentation and lactic acid. He says that the process 

 of anaerobic respiration in plant-cells is a fermentation directed 

 by this lactolase. 



The phytin of Posternack has been shown capable of hydrolysis 

 by an enzyme, phytase, into phosphoric acid and the cyclic 

 carbohydrate inosite. The former is a possible source of phos- 

 phorus-supply for the cell-nucleins, and the inosite further breaks 

 up into lactic and other fatty acids. This phytin, which contains 

 80 % of the phosphorus of seeds, is built of three double formal- 

 phosphoric ester groups, condensed as inositephosphoric ester.(15) 

 We see in this new substance vast possibilities — how inorganic 

 phosphates may unite with the first product of photosynthesis, 

 and (somewhat like the acetone-mesitylene condensation) produce 

 a cyclic compound. From the latter the phosphate radicle 

 separates and gives rise to inosite, and from inosite a number of 

 fatty acids have been formed. 



The fats circulate in the plant as glycerol and free acids. This 

 separation is the work of the enzyme, lipase, which is able to split 

 the fats or recombine their products according to requirements. 

 The presence of a hydrolytic fat enzyme in plants was first 

 suggested by Pelouze(16) in 1855, and conclusively proved by 

 Green(17) in 1890. Since then, a large number of seeds and 

 other parts of plants have been examined, and the evidence 

 points to the presence of a zymogen or dormant enzyme in the 

 resting seed, though some resting seeds are slightly hydrolytic. 

 When such oily seeds germinate, the enzyme is activated into 

 lipase and the fatty oils rapidly hydrolyse; this is the first step 

 in the utilisation of fats as food-material for the developing 



