MISCELLANY. 
75 
dust generated by the sorting of the leaves is not met with in the Euro- 
pean markets, as it is kept for home consumption. An intentional 
adulteration of senna with other leaves in their native country is out of 
the question, for the slightest adulteration is there punished as a capital 
crime. The small pods, which are rarely found mixed with the leaves 
because they are carefully picked out, are in very general use in the 
countries where the senna grows. In the bazaars of Constantinople 
and Smyrna two varieties are met with — an Egyptian and a Tripolitan 
variety. — Ibid. 
Transparency of Quieksilver. — M. Melsens has found that quicksilver 
in minute globules is transparent, and transmits a blue light slightly 
tinged with violet. These globules are formed when a fine stream of 
water is dropped on a mercury-bath ; the drops of water, in consequence 
of falling with some force, become covered with a thin pellicle of mer- 
cury, which present the fact here stated. The result has been verified 
by Aragc. — Chem. Gaz., from L'Institut. 
Experiments on the Milky Sap of the Cow-Tree. By Heintz. — It is 
now a considerable time since the milky sap of the palo de vaca was ex- 
amined by Messrs. Boussingault and Mariano de Rivero, who found it 
to contain water, wax, a substance identical with animal fibrin, sugar, 
and a magnesian salt, free from acetic acid. 
Since the experiments of these philosophers, M. Solly also made 
several imperfect experiments on this liquid, according to which he dis- 
covered water, a resinous or waxy substance, gum, saline substances, 
probably acetate of magnesia, gluten and albumen. 
Five years ago many experiments on the same subject were published 
by M. Marchand. This chemist found, in the sap that came from the 
Caraccas, water, sugar capable of fermentation, lime and magnesia in 
combination with phosphoric acid, traces of acetic and butyric acids, a 
substance resembling caoutchouc, and various resinous matters. 
We have now before us a statement of new experiments, made by M. 
Heintz, on different samples of the milk of the cow-tree. According to 
this author the sap contains 42.7 per cent, of solid substances, that is to 
say — 
Water 57.3 
Vegetable albumen . . . 0.4 
Waxy matter .... 5.8 
Resinous matter . . . 31.4 
Gum and sugar . . . 4.7 
Fixed salts . . . . 0.4 
In a sample of damaged sap, M. Heintz also discovered traces of bu- 
