CARBOHYDRATES AND FATS 41 



the seed-leaves assume the functions of foliage leaves a reduc- 

 ing sugar appears, and, in a short time, is the only sugar 

 present. In the hypocotyl and roots the amount of sugar 

 rapidly increases until in seedlings about 4 inches long it may 

 amount to 20 per cent of the dry weight, then a gradual 

 decrease takes place. There is also a small increase in the 

 amount of starch. 



The nature of the carbohydrate differs in different plants ; 

 thus in addition to the above-mentioned plants, during the 

 germination of Allium and of Cucumis much glucose makes its 

 appearance ; this is also true, although to a lesser degree, for 

 Cannabis sativa, in which case the glucose is quickly trans- 

 formed into starch. 



In other instances starch is said to be the carbohydrate 

 formed. 



It is thus seen that there is an intimate connexion between 

 carbohydrates and oil, and the question naturally arises how 

 is the one connected into the other, to which there is no 

 answer. 



The consideration of the formulae of the substances in ques- 

 tion shows that fats poor in oxygen give rise to carbohydrates 

 rich in oxygen, and vice versa ; but as to how this is accom- 

 plished nothing of a definite nature is known. 



Many suggestions have been put forward, and before 

 mentioning these the reader may be reminded of the large 

 amount of oxygen which is absorbed during the germination 

 of oil-containing seeds. 



Detmer considered that starch may arise from the free 

 oleic acid according to the equation : 



C 18 H 34 2 + 2 7 = 2 (C 6 H 10 5 ) + 6C0 2 + 7 H 2 



According to Maquenne the sugar has an origin depending 

 upon the nature of the oil ; thus if the fat be saturated, of 

 its hydrolytic products the glycerine gives rise to the sugar, 

 whilst the fatty acids are used up in oxidative processes. 

 If, on the other hand, the fat be unsaturated, the fatty acid 

 contributes to the formation of the sugar. 



This change is supposed to be effected by the oxidation 

 of the chain at the double bond setting free two unsaturated 

 groups which by polymerization give rise. to sugar. 



