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XV. Some Experiments on the Milk of the Cow- Tree. By THO- 

 MAS THOMSON, M. D. F. R. S. L. & E. &c. Professor of 

 Chemistry in the University of Glasgow. 



(Read llth March 1828J 



A PHIAL full of this liquid, one of the first specimens, I believe, 

 that ever made its way to Great Britain, was lately sent to Dr 

 HOOKER by Sir RALPH WOODFOBD, Governor of Trinidad. It 

 had been collected in Laguayra by Mr LOCKART, Director of the 

 Botanic Garden in Trinidad. Dr HOOKER having been good 

 enough to put this rare specimen into my possession, I made a 

 few experiments to determine its constituents. The singular 

 nature of the production, rather than any thing very striking in 

 the results which I obtained, led me to suppose that they would 

 not be unacceptable to the Royal Society. 



This curious vegetable production was first made known to 

 the scientific world by M. DE HUMBOLDT. But from the very 

 imperfect account which he gives of the Galactodendron utile *, 

 there is reason to conclude that he had never seen it. It is cer- 

 tain at least that he had never seen it in blossom. The atten- 

 tion of MM. BOUSSINGAULT and MARIANO DE RIVERO was drawn 

 to this important liquid by M. DE HUMBOLDT. They collected 

 it accordingly, and subjected it to a chemical examination. They 

 found its constituents to be wax, fibrin, sugar, a magnesian salt, 

 which was not an acetate, and water. They could neither de- 

 tect in it casein nor caoutchouc. The ashes after incineration 



* This is the name given by HUMBOLDT to the tree which yields the cow-tree 

 milk. 



VOL. XI. PART II. H h 



