268 FOOD FROM WOOD. 



EXPLANATION OF PLATE XVIII. 



Fi^. 1. — The Calcareous Rosette or disc of sucker foot of Eclu)ius 

 escuhntns, showing the foot-ring or " psellion " in situ, x 100. 



2 and 3. — Loose plate of the "psellion," showing the calcified 

 areolar condition, x 200. 



4. — The plates of the Foot-ring as placed in position, x 250. 



5. — The buccal membrane surrounding the teeth of Echinus 

 esculentus, with the ten buccal plates in situ (the tentacles 

 proceeding therefrom being dissolved away in liquor potasste), 

 X 6. 



6. — One of the imbricated plates from the surface of the buccal 

 membrane, highly magnified. 



^O" 



n 



55 



5? 



jfooD from IMool). 



Probably no modern science presents a wider iield for specula- 

 tion than that of chemistry, and more especially, perhaps, that 

 branch of the science which treats of organic compounds. 



In an address delivered at Heidelberg by no less eminent an 

 authority than Victor Meyer, it is announced " that we may reason- 

 ably hope that chemistry will teach us to make the fibre of wood 

 the source of human food." What an enormous stock of food, 

 then, will be found, if this becomes possible, in the wood of our 

 forests, or even in grass and 5traw. The fibre of wood consists 

 essentially of cellulin. Can this be made to change into starch ? 

 Starch has essentially the same percentage in composition, but, 

 as every one knows, it differs very much in its properties, and the 

 nature of its molecules is probably much more complex. Cellulin 

 is of little or no dietetic value, and is not altered, like starch, in 

 boiling water. It readily gives glucose when treated with sul- 

 phuric acid, as is easily shown when cotton w^ool, which is 

 practically pure cellulin, is merely immersed in it. Starch gives 

 the same product when boiled with weak acid. 



The author further quotes the researches of Hellreigel, which 

 go to show beyond dispute that certain plants transform atmo- 

 spheric nitrogen into albumen, and that this process can be 

 improved by suitable treatment. The production, therefore, of 

 starch from cellulin, together with the enforced increase of albumen 

 in plants, would, he adds, in reality signify the abolition of the 

 bread question. It must be borne in mind, however, that theory, 

 fascinating and promising though it may be, is not always capable 

 of being followed up by a practical result. — Ktihloiv. 



