The Last Word 253 



ginous mass in which the beans are imbedded, 

 and on the other the changes that the sub- 

 stances in the. beans themselves undergo. 

 This can be described as external and internal 

 fermentation. 



The juice of the pulp, according to my 

 investigations, contains about 10 per cent, of 

 sugar (dextrose and laevulose), 3 per cent, of 

 mucin, and besides this, as much acid (chiefly 

 malic acid) as corresponds to -f^ (i in 10) 

 normal solution. The specific gravity at 15 C. 

 amounted to 1*06308, 100 c.cm. of juice con- 

 tained 0*638 grm. of mineral ash, of which 

 0*192 grm. consisted of calcium carbonate, and 

 o' 1 96 grm. magnesium carbonate. After hydro- 

 lysis of the mucilaginous substances a pentose 

 and dextrose were proved to be present. No 

 difference in the Criollo and Forastero varieties 

 could be demonstrated as to the composition 

 of the juice. The pulp is, therefore, a good 

 nutritive medium for a large variety of micro- 

 organisms, both yeasts and tacteria. The 

 different methods of conducting fermentation 

 are well enough known. The guiding prin- 

 ciple is always to turn over the heaps the 

 moment the temperature begins to fall, in 

 order that the micro-organisms may be stimu- 

 lated to renewed activity by the advent of 

 oxygen. In the first place, the sugars are 

 converted into alcohol, then oxidation fer- 

 mentation sets in, acids, especially acetic acid, 

 being formed. Under normal circumstances 



