i8o 



BOTANY AND PHARMACOGNOSY. 



While some of the vegetable ferments have been isolated and 

 are prepared on a commercial scale, as diastase and the peptic 

 enzyme papain found in the latex of Carica papaya, in other 

 cases the ferment-producing organisms themselves are used in a 

 number of industries involving fermentation processes, as the 

 yeast-plants and certain of the molds and bacteria. 



The microchemical study of the ferments is attended with cer- 

 tain difficulty on account of the lack of specific reagents for their 

 detection. The most that can be done is to study the products 

 formed by their action upon certain other constituents of the cell. 



Enzymes may be divided into two classes according to 

 whether they introduce oxygen or the elements of water sub- 

 stances, (i) The former are called oxidase enzymes, and are 

 rather limited in number, and include laccase, found in the lacquer 

 trees, and those which produce nitric fermentation in nature. 

 (2) The latter or hydrolytic enzymes include diastase, which acts 

 on starch, changing it into dextrose; inulase, which acts on inu- 

 lin, producing levulose ; pectase, acting on pectin, producing vege- 

 table jellies ; emulsin or sinaptase, which decomposes amygdalin, 

 arbutin, salicin and other glucosides ; myrosin, which acts on the 

 glucoside sinigrin (potassium myronate), producing the essen- 

 tial oil of mustard, and papain the proteolytic enzyme of Carica 

 papaya. 



EXAMINATION OF CELL-CONTENTS. 



I, 2 and 3 have characteristic appearance (see Frontispiece). 

 4. Crystals of characteristic shape, soluble in hydrochloric and 

 insoluble in acetic acid. 5. Crystalline in fresh material treated 

 with alcohol. The glucoses give a reddish precipitate with Fehl- 

 ing's solution. 6. Concentrated sulphuric acid gives either a 

 distinct color reaction, as with strophanthus (p. 431), or the sep- 



