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SELECTED ARTICLES. 
termined by means of very definite combinations, would be 
much more like to promise important results from their study. 
I had the good fortune, at the very commencement, to com- 
bine salacin with the oxide of lead. The analysis of this com- 
bination enabled me to establish the formula of salacin, both in 
a free state or when combined. This first step encouraged me 
to pursue my researches upon this, as I then supposed, sterile 
subject, but which I soon found to be very fruitful in new and 
interesting results. I do not flatter myself that these labors 
have completed the study of salacin; on the contrary, the sub- 
ject is far from being exhausted. The long and expensive 
process which I employed to procure the hyduret of salicyle, 
the substance by means of which the interesting compounds, 
the objects of these researches, were obtained, prevented me 
from obtaining a large quantity of the products, and thus I was 
unable to make the study of each as complete as I would have 
desired. I nevertheless hope at some future time to fill up 
the deficiencies of the present paper. 
I cannot, without being deficient in gratitude, pass without 
acknowledgment, the kindness of M. Dumas, in allowing me 
the use of his laboratory, and aiding me with his advice during 
these researches. 
Salacin in a free state. 
This matter is white, crystallized in plates, soluble in water 
and alcohol, insoluble in ether, fusible below 100°; it does not 
contain nitrogen, and does not loose water when exposed to 
a temperature of 200° — sulphuric acid communicates to it a 
beautiful and intense red color. The action which weak acids, 
oxidating bodies, chlorine, &c. exercise upon it, will be detail- 
ed in the course of this paper. 
The elementary composition of salacin was determined by 
MM. Pelouze and J. Gay-Lussac. According to these chemists, 
it is composed of 
