LIXIVIATION OF VEGETABLE AND ANIMAL SUBSTANCES. 223 
the influence exercised on the results, by the mixture of the 
different strata of fluid, and has arrived at a conclusion differing 
widely from that of MM. Boullay, for he has found that these 
strata readily mix with each other. After M. Guillermond 
finished his researches, I continued them on other substances, 
and I found, as he had done, that a certain number of bodies 
were not suited to this process. Called off from the subject by 
other occupations, I have since again taken it up, and the re- 
sults of numerous experiments have led me to a modification 
of my previous opinions. I had already operated on a great 
variety of substances when I became acquainted with an un- 
published memoir by M. Dausse on the same subject. M. 
Dausse subjected to lixiviation, both with water and alcohol, 
near eighty different bodies; my experiments were on sixty of 
these, and on eleven not noticed by him. The result has been 
a mass of facts which permit a more exact appreciation of this 
mode of operating. 
The best apparatus that can be used is that described by 
MM. Boullay; it consists of a cylinder of tin plate, about four 
times longer than broad, terminated below by a funnel; about 
the middle of this cone or funnel is a septum or diaphragm, 
pierced with holes, which when used is to be covered with a 
thin layer of carded cotton ; over this is to be placed the pow- 
der to be operated upon, and this covered by another pierced 
plate. The apparatus should not be too large, it should not 
contain more than 4 or 5 lbs. of powder; if a larger quantity of 
any article is to be treated, it is better to divide it between se- 
veral different instruments. It is also essential that the lower 
part be furnished with a stop-cock. This apparatus is calcu- 
lated for water or alcohol; if etherial solutions are wanted re- 
course should be had to the apparatus of M. Robiquet. 
The degree of fineness of the powder has much influence 
on the result. It is from using substances too finely pulverized 
that both M. Guillermond and myself as well as the MM. 
Boullay have thought that those articles which contained 
much mucous matter could not be advantageously treated by 
this process, but the fact is, onthe contrary, that there are very 
few substances to which it is not applicable. 
