358 HOW CROPS GROW. , 



dextrin, gum, the sugars, and soluble proteids. The 

 water whicH the seed imbibes, to the extent of one-fourth 

 to five-fourths of its weight, at once dissolves them. 



It is otherwise with the fats or oils, with starch and 

 with proteids, which, as such, are nearly or altogether 

 insoluble in water. In the act of germination provision 

 is made for transforming these bodies into the soluble 

 ones above mentioned. So far as these changes have 

 been traced, they are as follows : 



Solution of Fats. — Saohs was the first to show that 

 squash-seeds, which, when ripe, contain no starch, 

 sugar, or dextrin, but are very rich in oil (50%) and 

 albuminoids (40%), sufEer by germination such chemical 

 change that the oil rapidly diminishes in quantity (nine- 

 tenths disappear), while, at the same time, starch, and 

 in some cases sugar, is formed. {Vs. St., Ill, p. 1.) 



Solution of Starch. — The starch that is thus organized 

 from the fat of the oily seeds, or that which exists 

 ready-formed in the farinaceous (floury) seeds, undergoes 

 further changes, which have been previously alluded to 

 (p. 50), whereby it is converted into substances that are 

 soluble in water, viz., dextrin and dextrose. 



Solution of Albuminoids. — Finally, the insoluble al- 

 buminoids are gradually transformed into soluble modi- 

 fications. 



Chemistry of Malt. — The preparation and proper- 

 ties of malt may serve to give an insight into the nature 

 of the chemical metamorphoses that have just been 

 indicated. 



The preparation is in this wise. Barley or wheat 

 -(sometimes rye) is soaked in water until the kernels are 

 soft to the fingers ; then it is drained and thrown up in 

 heaps. The masses of soaked grain shortly dry, become 

 heated, and in a few days the embryos send forth their 

 radicles. The heaps are shoveled over, and spread out 

 so as to avoid too great a rise of temperature, and when 



