464 
REVIEW OF MOIROUD’s 
When they are really indicated, their use should be persisted 
in for a considerable time. Tonics are often confounded with sti¬ 
mulants. The object of both is to rouse the powers of the system. 
The stimulants are preferable when there is marked inactivity of 
various organs, and it is necessary to excite a kind of medicinal 
commotion. 
Tonics are indicated when we wish to produce a permanent 
effect—to arouse the energy of certain organs without awakening 
their sensibility, without quickening the circulation or increasing 
the animal heat. 
Iron. —The different preparations of this metal act upon the 
constitution in a somew 7 hat similar manner. Applied to the skin 
they produce no effect. Their action is scarcely appreciable when 
brought into contact with a wound or abraded surface; but when 
they are introduced into the alimentary canal they are slightly 
astringent, and they produce a tonic effect, powerful in propor¬ 
tion as the organic tissue was weakened. Under their influence 
the appetite is increased, fsecal discharges are lessened, and are 
of greater consistence, and more deeply coloured. 
These phenomena, however, do not manifest themselves im¬ 
mediately, for the tonic action of the preparations of iron, is very 
slow in developing itself; but that action always finishes by being 
propagated from the digestive to the circulatory system, and thence 
to the whole frame. This species of diffusion seems to depend 
in a great measure, on the molecules of the iron actually mingling 
with the blood, and for which they seem to have a peculiar affi¬ 
nity. These molecules being easily absorbed by the inhalent 
mouths of lymphatic absorbents, enter into the circulation, and 
accompany the blood through the whole of its course, and pene¬ 
trate into the parenchyma of the organs. They are also found in 
the urine. 
Preparations of iron are used to combat debility of the diges¬ 
tive organs, chronic diarrhoea without inflammation, passive 
dropsy, the aqueous cachexy of sheep (the dropsy and decom¬ 
position of all the fluids which accompanies the last stage of the 
rot?) and certain chronic enlargements which seem to belong 
particularly to the lymphatic system. Many practitioners say 
that they have obtained unexpected success by the use of one of 
them (carbonate of iron) in some nervous diseases, and especially 
in those painful nervous affections, which have an intermittent 
type with occasional exacerbations. 
Most of these preparations are given to animals in a state of 
powder, made into a mass with honey, extract of juniper, and 
some farinaceous substance, and in doses of f rom one to three ounces 
for the horse and cattle, and from one drachm to four for sheep. 
