C08 THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. [January 27,1872. 
The spectrum resembles that of blood, but differs from 
it sufficiently so as to distinguish one from another for 
practical purposes. These hands are not produced by 
any other evacuations known, and we have therefore in 
them a diagnostic sign of the highest value to dis¬ 
tinguish in doubtful cases sporadic cholera from the 
true Asiatic disease. The source of this pigment in 
cholera is probably the hsemato-crystalline, split up and 
morbidly charged by the destructive chemolytic power 
of the cholera poison. 
“ The spectrum has also thrown a considerable light 
upon the cause of some of the symptoms in Bright's 
disease , hitherto little understood. "We all know that 
uncontrollable retching and vomiting are often a constant 
symptom in chronic renal disease. This is probably 
produced by two new bodies, discovered by Dr. Thu- 
dichum. They are decomposition products, derived 
from urochrome, viz. omicholine and omicholic acid, and 
are formed within the economy in certain diseases of 
the kidney. They possess highly nauseating and emetic 
properties, and probably cause that uncontrollable irri¬ 
tation of the stomach, especially in cases where, by an 
irrational treatment, salutary evacuations have been 
repressed, and the task to relieve the system of this 
noxious product has been thrown upon the stomach. 
These bodies can be readily demonstrated by the spec¬ 
trum test. Uromelanine, a decomposition product from 
urine, can also be easily detected. It is often coincident 
with melanotic disease, and points at grave disordered 
assimilation and imperfect decarbonization of the blood. 
A substance always found in connection with it is para- 
melanine. This is an interesting body, as it yields to 
the spectroscope characteristics of cruentine, thus reveal¬ 
ing its true origin from the blood. 
“ Spectrum analysis has recently been employed in 
experiments to demonstrate minute quantities of vege¬ 
table poisons and their alkaloids, such as strychnine, 
veratrine, atropine and others. The experiments, al¬ 
though not completed, are promising very interesting 
results. Metallic poisons, such as arsenic, copper, anti¬ 
mony, lead, thallium and barium, can be most readily 
detected by bringing them into a state of incandescence, 
when each will show its own peculiar modification of 
the spectrum. Many of the tinctures and solutions of 
narcotic poisons give characteristic absorption bands; 
and by the aid of the spectroscope we can detect adulte¬ 
rations of wine and fermented liquors, as also the age of 
wines and the quality and purity of fixed and volatile 
oils.” 
NATURAL NITRIFICATION. * 
BY M. BERTHELOT. 
The fullest experiments that have been made on the 
chemical conditions of nitrification are even now those of 
MM. Thouvenel,f although they were made nearly a 
century ago. These experiments show that nitrification 
is principally effected upon the gaseous products of pu¬ 
trefaction ; that it proceeds better in the presence of 
alkaline or earthy salts than in their absence ; and that 
it scarcely takes place but with carbonates, and not at all 
with sulphates. 
The results of these experiments are to be accounted 
for by considering that the disengagement of the ammonia 
furnished by the nitrogenous organic matters occurs 
only in an alkaline medium; that it cannot take place 
in one capable of forming by double decomposition only 
fixed and neutral salts such as the sulphate; and that, 
on the other hand, its occurrence is facilitated when the 
liquor can give rise to a volatile ammoniacal salt, like 
the carbonate. The presence of a fixed alkali or of an 
alkali cai+onate determines also the generation of am¬ 
monia at the expense of the nitrogenous matters. More- 
* Ann. Chem. Pliys. [4], xxii. 87-96; from the Journal of 
the Chemical Society. 
t Mem. de l’Acad. des Sciences (Sar. etrang.), xi. 1787. 
over, the presence of an alkali or of a salt with alkaline 
reaction is very efficacious in accelerating the oxida¬ 
tion of organic matters by the air at ordinary tempera¬ 
tures. 
Even the way in which the oxidation of the ammonia 
proceeds, aids in explaining the efficacy of the fixed 
alkalies and their carbonates. For the slow oxidation of 
ammonia develops nitric acid, and this can only unite 
with the unchanged ammonia to form ammonia nitrate, 
a fixed salt without alkaline reaction. But the presence- 
of an alkali carbonate preserves the alkalinity of the 
liquor, as it transforms the ammonia nitrate into fixed 
alkali nitrate and into ammonia ready for an ulterior 
oxidation. 
A comparison of these different circumstances, with 
the quantities of heat disengaged by them, throws con¬ 
siderable light upon the degree of their participation 
and importance in nitrification. 
Transformation of ammonia into nitric acid and into 
ammonium nitrate:— 
Ammonia . . . NH 3 + 0 4 = N0 3 H + H 2 0 
Ammonia nitrate 2NH 3 -f 0 4 = N0 3 H.NH 3 + H 2 0. 
The formation of gaseous ammonia from its elements, 
N + H 3 = N H 3 , disengages, according to Favre and 
Silbermann, 22,700 heat-units (22,500) ; that of dis¬ 
solved ammonia, N + H 3 = n Aq = N H 3 n Aq, disengages. 
31,500 ; lastly, the formation of water, H 2 + O = H 2 0, 
disengages 69,000 or 59,000, according as the water is 
produced in the liquid or in the gaseous state. 
Hence it follows that the oxidation of ammonia disen¬ 
gages the following quantities of heat, according to the 
nature and the state of the products to which they give 
rise:— 
(1) Formation of Nitrogen : 
2NH 3 + 3 0 = N 2 + 3H 2 0. 
Ammonia gaseous and 
water gaseous . . . 177,000 — 45,000 = 132,000> 
Ammonia dissolved and 
water liquid .... 207,000 — 63,000 = 144,000- 
Ammonia gaseous and 
water liquid .... 207,000 — 45,000 = 162,00ft 
(2) Formation of nitric oxide :* 
2 NH 3 + 5 O = N 2 0 2 + 3 H,0. 
Ammonia gaseous and water gaseous . . . 146,000' 
Ammonia gaseous and water liquid .... 176,00ft 
■ (3) Formation of nitrous acid: 
2 NH 3 + 60 = 2 N0 2 H + 2 H 2 0. 
Ammonia gaseous, water liquid, nitrous acid 
dilute. 163,000' 
(4) Formation of nitric acid : 
2 NH 3 + 80 = 2 N 0 3 H + 2HoO. 
Ammonia gaseous, water and nitric acid ga¬ 
seous, about. 162 00ft 
Ammonia gaseous, water liquid, nitric acid 
dilute.217,000 
Ammonia dissolved, nitric acid dilute . . . 199,000 
(5) Formation of ammonia nitrite in solution : 
2 NH 3 + 3 O = N OoH.NH 3 + HoO. 
Ammonia gaseous, nitrite dissolved, about . . 104,000- 
_ The reaction of the same bodies producing water and. 
nitrogen develops half as much more heat (162,000) ; 
ammonia nitrite also very readily decomposes into ni¬ 
trogen and water. 
(6) Formation of ammonia nitrate in solution : 
2 NH 3 + 40 = N0 3 H.NH 3 + H 2 0. 
Ammonia gaseous, nitrate dissolved .... 131,00ft 
* Ann. Chem. Pliys. [4], xxii. 75. 
