ADULTERATIONS OP ALIMENTARY" SUBSTANCES. 281 
ordinarily acts only five or six hours after it is taken, rarely 
after, more rarely before. 
As the action of the magnesia is slow in appearing, it is 
well to observe here Jthat it is not necessary to await its 
effects to take food; it may be taken, without inconvenience, 
three hours after its administration. — Ibid. 
ART. LX. — ON THE ALTERATIONS AND ADULTERATIONS 
OF ALIMENTARY SUBSTANCES. 
BY A. CHKVALLIER. 
The following petition was addressed by M. Chevallier 
to the Chamber of Peers and the Chamber of Deputies ; but 
the Session was terminated without its having been made 
the subject of a report as to the measures to be taken for 
the prevention of the frauds specified in it: 
To the Members of the Chamber of Peers, and to the 
Members of the Chamber of Deputies. 
Gentlemen, — Before determining to avail myself of the 
right of petition, which belongs to every citizen, and before 
resolving on disturbing your numerous and important occu- 
pations, I have considered it my duty to ask myself whether 
the abuses which I think it my duty to lay before you were 
serious — whether they were of a nature to injure com- 
merce — whether they might compromise the life and health 
of mankind— finally, whether they deserve special atten- / 
tion. 
The serious examination which I have made of every 
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