DEFINITIONS AND DESCRIPTIONS. 135 



30. Coffee bean is the fruit of the coffcea Arahica, and is in 

 general use for the manufacture of coffee. The tree is a native 

 of Arahia, but is extensively cultivated, both in the East and 

 West Indies. It contains a peculiar principle called caffein 

 (C4H2NO=48.5). According to the analysis of Hermann, the 

 coffee bean, from Martinique, contains 



Resin 68. I Lignin 11386 



Extractive 310. Loss 12 



Gum 144. 



1920 



31. Hops ave obtained from the humulus lupilus, and are em- 

 ployed extensively in the manufacture of beer and ale. The 

 hop is a dioecious plant, the female alone bearing fruit. It is 

 a valuable plant, and was introduced into England in the reign 

 of Henry the VIII. 



32. Dates are the fruit of the palm, [pTicznix datilyfera^) and 

 constitutes an important article of food in several warm coun- 

 tries. It has a sweet taste, and contains a large quantity of 

 sugar. 



This catalogue of fruits and seeds, and other products of the 

 vital principle, might be increased ; but a sufficient number 

 liave been noticed here to give the reader some idea of their 

 number, variety, properties and uses. They are intended chief- 

 ly, as a convenient reference to those who may not have access 

 to better sources of information. 



There are several other simple bodies contained in vegetables 

 besides oxygen, hydrogen, carbon and nitrogen ; but as they do 

 not, by their combinations, form the peculiar products of the 

 vital principle, they are not noticed in this place. They will 

 more properly come under review in the next two sections, which 

 treat of the source and assimilation of the simple substances 

 which enter into the composition of plants. It should also be 

 remarked, that those substances which nourish vegetables, are 

 often derived from organic bodies, and that many compounds 

 are classed a$ organic, simply because they are derived from 

 organic bodies. But they are the products of death or decay^ 

 not of life. 



Sect. 2. Dejinitions and Descriptions. — Source and as- 

 similation of the Organic Constituents of Plants. 



1. Humin is a substance found in the soil. It is composed 

 of carbon, hydrogen and oxygen, and is similar to woody fibre. 



