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COMPTE RENDU OF THE 
and which, as is well known, contributes so materially to fertilize the 
soil of Egypt in those plains that are inundated when the river 
annually overflows. 
One solitary analysis, made thirty years ago, attributed to this 
mud a composition which the recent progress of chemistry could 
not admit. With the view of testing these results afresh, M. 
Lassaigne has this year submitted a portion of the mud, brought 
to him by the Count Gasparin and M. Elie de Beaumont, to a strict 
chemical and experimental investigation. 
The result which he has obtained, and which he hastened to 
make known to the Academy of Sciences, is as follows, namely, 
that the mud may be regarded as an argilo-calcareous earth 
mingled with a certain quantity of uhnic acid and of azote- 
organized matter similar in nature to that found in good soils or 
in manure. The presence of this latter principle, which constitutes 
the basis of the artificial soils so much esteemed in agriculture and 
horticulture, although in themselves remarkable, fully explains the 
advantages arising from it as a manure. It is probable that its 
beneficial effects on the sandy Egyptian soils over which it spreads 
itself are caused by its acting in two ways, — amending the constitu- 
tion of the sandy soil, and depositing therein the rich earthy matter 
that it contains, and which becomes useful to the plants that grow 
there. The same Professor is also occupied, whenever occasion 
presents itself, in submitting to a chemical analysis the various 
pathological productions collected either in the course of the opera- 
tions performed at the School, or in the anatomical museums by 
dissections. A new analysis of a salivary calculus, extracted from 
the canal of the right maxillary gland of a living horse by M. 
Prudhomme, has demonstrated that this calculus, which contained 
among the number of its constituent parts carbonate of lime, 
mingled with a small quantity of calcular phosphate, had for a 
kernel or central point a grain of oat. This observation, which 
had been previously made on some salivary calculi found in horses 
and other herbivorous animals, proves the influence exercised by 
foreign bodies that have accidentally found their way into these 
salivary canals, on the precipitation of the calcareous salts held in 
solution by the saliva. % 
The dissolvent action exercised by the gastric juice on the ali- 
mentary matters contained in the stomach, has, since the time of 
Spallanzani, excited the attention of a great number of physiolo- 
gists and chemists. These latter by no means agree as to the 
principles that enter into the composition of this fluid. Some ex- 
periments, undertaken by the Professor of Pathology, enabled him 
to collect a certain quantity of gastric juice, which he immediately 
submitted to a careful analysis. The result of this has been to 
