328 QUARTERLY JOURNAL 



peaSj or to that of the cow, barley straw or clover, which are rich 

 in salts of lime, the health of the animal is sustained.* 



Men and animals receive their blood and the principles of their 

 bodies from the vegetable kingdom, and an inscrutable wisdom has 

 ordained that the life and the vegetation of the plant should be 

 connected by the closest links with the absorption of the same mi- 

 neral substances that are indispensable to the animal organism. 

 Without those inorganic matters which we know to be principle 

 of their ashes, it is impossible to form an idea concerning the for 

 mation of the germ, of the leaf, of the flower, and of the fruit 



The quantity of the principles serving for the nourishment o; 

 animals is extremely unequal in the cultivated plants. 



There is a much greater relation between tubercles and roots, 

 with respect to their chemical principles, than with the seeds. The 

 latter have always a similar composition. 



Potatoes, for example, contain from 75 to 77 per cent of water, 

 and from 23 to 25 per cent of solid substance. By means of a 

 mechanical operation, we can decompose the latter into 18 or 19 

 parts of starch, and three or four parts of dry, amylaceous fibre. 

 It is easy to see that the two combined, weigh almost as much as 

 the dry potatoes themselves. The two hundredths which are 

 wanting are formed of salts, and of the sulphuro-nitrogenous sub- 

 stance known under the name of albumen. 



Beet roots contain from 88 to 90 per cent of water, 25 parts of 

 beet roots contain very nearly the same elements as 25 parts of 

 dried potatoes. We found from 18 to 19 parts of sugar, and 3 or 

 4 parts of cellular tissue ; half of the two hundredths which are 

 wanting is formed of salts ; the rest is albumen. 



Turnips contain from 90 to 92 parts of water. From 23 to 25 

 parts of dry turnips contain from 18 to 19 parts of pectine, with 

 very little sugar, three or four parts of cellular tissue, and two 

 parts of salts and albumen. Sugar, starch, and pectine contain no 

 nitrogen ; they are met with in plants in the free state, never in 

 that of combination with salts or alkaline bases. These are com- 

 binations formed by the carbon of the carbonic acid, and the prin- 

 ciples of water, whose elements take the form of starch in the po- 

 tatoe, that of sugar in the beet-root, and that of pectine in the 

 turnip. 



We have as a sulphuro-nitrogenous principle, in the seeds of 

 cereals, vegetable fibrin; in peas, beans, and lentils, casein; in the 



• The workmen, in the mines of South America, whose daily work (perhaps the 

 hardest in tlie world,) consists in raising' on their shoulders, from a depth of l-Rim. 178, 

 a charge from the mine of the weight of from 5)0 lo ItX) kil., live only on bread and 

 beans; they would prefer bread alone for their nourishment; but their masters, who 

 have fountl (hat they cannot work so hard with bread alone, treat them like horses, and 

 force them to eat beans, [Darwin, Journal of Researches, \i. 324.] But beans contain 

 proportionally, much more of the eartliy substance of the bones than bread. 



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