14 Dr. Thomson's Analysis of Ceradia Resin. 



V. — On the Acid of the Stomach and on the Digestion of Vegetable 

 Albumen, Fat and Starch. By Robert D. Thomson, M.D. 



This paper has been printed at length in the Philosophical Maga- 

 zine for April and May, 1845. The object of the communication was 

 to prove by experiment, 1. That when albumen and fat are used as 

 articles of food, they can be detected, the former only in minute 

 quantities, during a certain space of time in the circulation. 2. That 

 when starch is swallowed, after having been boiled, it is first con- 

 verted into dextrin or soluble starch, and then into sugar. 3. That 

 sugar exists in the blood in considerable quantities when starch has 

 been employed as an article of food. 4. That no free hydrochloric 

 acid exists in the stomachs of animals during the digestion of starch. 

 5. That an acid exists in the stomachs of animals fed on starch, which 

 corresponds more nearly with the lactic than with any other known 

 acid. 



Dr. Balfour exhibited a specimen of Ceradia furcata, a singular 

 plant from the coast of Africa, opposite Ichaboe, presented to him by 

 Mr. Alexander Bryson of Edinburgh. It is a shrub, having the 

 appearance of coral, belonging to the natural order Composita3, 

 section Erecthitese of Decandolle, and allied in many respects to the 

 genus Kleinia. The plant yields a resin possessing an odour resembling 

 that of Olibanum. 



VI.— Analysis of Ceradia Resin. By Robert D. Thomson, M.D. 



The resin possesses an amber colour, and an odour similar to that 

 of Olibanum. It partially dissolves in alcohol, and is precipitated by 

 water. Caustic ammonia produces no precipitate in the alcoholic 

 solution. The alcoholic solution possesses a slightly acid reaction, and 

 is not precipitated by nitrate of silver. Specific gravity 1-197, 

 determined by my pupil, Mr. Hugh B. Tennent. 



Analysis gave the following results: — 



199 grains lost by exposure to the temperature of 212° for some 

 days 2*11 grains. During the whole of the period its peculiar odour 

 was emitted. Previous to being subjected to this heat it was pulver- 

 ized, but it speedily became soft, and collected into a mass. In this 

 state — when burned with oxide of copper and chlorate of potash — 



6*24 grains gave 18*33 grains C0 2 . 

 and 5-50 . HO. 

 This amounts to per cent. 



Carbon, . . . 80*113 



Hydrogen, . . . 9793 



Oxygen, . . . 10094 



100-000 



