PUT 
PUS 
Concentrated nitric acid effervesces with 
it, and forms a yellow solution, which when 
recent is decomposed by water, the pus 
subsiding in the state of grey flakes. 
Muriatic acid dissolves it when heated, 
and the pus is separated by water. 
With the fixed alkaline leys it forms a 
whitish ropy fluid, which is decomposed by 
water, the pus precipitating. Pure ammonia 
reduces it to a transparent jelly, and gra- 
dually dissolves a considerable portion of 
^'When nitrat of silver is dropt into the so- 
lution of pus in water, a white precipitate se- 
parates. Nitrat and oxymuriat ot mercury 
occasion a much more copious flaky preci- 
pitate. 
Such are the properties of healthy pus hi- 
therto observed by chemists. Various ob- 
servations have been made to enable physi- 
cians to distinguish pus from the mucus of 
the internal cavities, especially of the lungs. 
In cases of copious expectoration, it is some- 
times of consequence to know whethei the 
matter thrown out of the lungs is pus or 
mucus Mr. Charles Darwin made a set of 
experiments on the subject, and pointed out 
three criteria to distinguish pus: 1. Sul- 
phuric acid dissolves it. When the solution 
is diluted, the pus precipitates ; but mucus 
treated in the same manner swims. But this 
distinction depends upon the quantity of 
wa ter added, and is therefore ambiguous. 2. 
Pus is diffusible through diluted sulphuric 
acid through water, and through brine; but 
mucus is not. 3. Alkaline leys dissolve pus; 
water precipitates pus thus dissolved, but not 
mucus. Mow far these two last distinctions 
prevail is rather doubtful. Grasmeyer has pro- 
posed the following method, which he con- 
siders as complete : Triturate the substance 
to be tried, with an equal quantity of warm 
water ; then add to it an equal portion of a 
saturated solution of carbonat of potass, and 
set the mixture aside. If it contains pus, a 
transparent jellv subsides in a few hours ; 
but this does not happen if only mucus is 
present. 
2. When the ulcer is ill-continued, the pus 
secreted in it possesses different properties. 
It has usually a fetid smell, is much thinner, 
and to a certain degree acrid. We are in 
possession of two sets of experiments on this 
unhealthy pus: one by Mr. Cruickshank on 
the pus discharged from what is called the 
hospital sore ; another by Dr. Grawtoid on 
the matter of cancers. 
The pus from the hospital sore possesses 
most o f ' the properties of healthy pus ; but 
is distinguished by its odour, and by some 
shades of difference when exposed to the ac- 
tion of the metallic precipitates. Lime- 
water changes its fetid odour, but does not 
destroy it ; sulphuric acid increases it, as do 
alcohol and the solution of oxide of arsenic 
in potass. Bark has no effect upon it; but 
it is destroyed by the nitrat and oxymuriat 
of mercury, by nitric acid, and by oxymuri- 
atic acid. Nitrat of silver does not destroy 
it. Mr. Cruickshank supposes that the fetid 
smell is occasioned by the alteration of some 
part of true pus. He considers the pus of 
the hospital sore as a matter sui generis, 
which is capable of generating more, and 
even of producing an alteration in the sys- 
tem Hence to heal the sore the matter 
must be destroyed, and prevented from ap- 
pearing again. This was done by washing 
the sores with nitrat of mercury, diluted 
nitric acid, and oxy muriatic acid, at every 
dressing. This method constantly succeeded 
with Dr. Hollo, except when the sore was 
too large to admit it to be put in practice 
completely. 
3. The matter of cancer, examined by 
Dr. Crawford, gave a green colour to syrup 
of violets. Potass produced no change; but 
sulphuric acid extricated a gas which possess- 
ed many of the properties of sulphureted 
hydrogen. This gas lie supposes to exist in 
tlie matter united to ammonia. The pre- 
sence of this compound explains the effects 
of the matter of cancer and virulent matter 
in general upon metallic salts. . Dr. Craw- 
ford found that the odour of this matter was 
completely destroyed by oxymuriatic acid ; 
and therefore recommends it as a proper sub- 
stance for washing cancerous ulcers. 
4. Besides the species mentioned above, 
there arc many others which we know from 
their effects to be peculiar, though we can- 
not find any chemical distinctions between 
them sufficiently well marked. But that they 
are specifically different cannot be doubted, 
if we consider that every one of them pro- 
duces a disease peculiar to itself. 1 he mat- 
ter of small-pox, of venereal ulcers, of cow- 
pox, &c. may be mentioned as instances. 
The liquor which fills the cavities of the 
body in dropsy has a yellowish-green colour, 
and' is sometimes turbid, sometimes nearly 
transparent. As far as it has been examined, 
it agrees exactly with the serum of the blood ; 
and^ the liquid which makes its appearance 
when the epidermis is raised into blisters, is 
perfectly transparent and liquid. When the 
blisters are artificial, it is usually yellow, and 
has the odour of the blistering-plaster. From 
the experiments of Margueron, we learn that 
it is composed of the same constituents as 
the serum of the blood. From 200 parts of 
this liquid he obtained 
36 albumen 
4muriat of soda 
2 carbonat of soda 
2 phosphat of lime 
156 water 
200 . 
PUTLOGS, or PutlocKs, in building, 
are short pieces of timber about seven feet 
long, used in building scaffolds. They lie 
at right angles to the wall, with'one of their 
ends resting upon it, and the other upon the 
poles which lie parallel to the side ©f the wall 
of the building. 
PUTREFACTION. The rapidity with 
which animal bodies undergo decomposition, 
and the disgusting fetor which accompanies 
this decomposition, have long been consider- 
ed as some of their most striking peculiari- 
ties. This spontaneous destruction is deno- 
minated putrefaction. Considerable atten- 
tion has been paid to it by chemists. Bec- 
char and Stahl have described with fidelity 
the phenomena with which it is attended, 
and the circumstances necessary for its tak- 
ing place. To sir John Pringle we are in- 
debted for some important experiments on 
the method of retarding putrefaction ; neither 
are the experiments of Dr. Macbride less 
valuable, though the consequences which he 
p u T 32.5 
drew from them were erroneous. We are 
indebted also to Crell and Priestley for many 
valuable facts ; and to Berthollet and 1 .a- 
voisierfor the first attempts to determine the 
real changes which take place, and the man- 
ner in which the new products which appear 
during putrefaction are formed. But not- 
withstanding the labours of these philoso- 
phers, and of many others, much is still want- 
ing to enable us to trace the complicated 
changes which take place during putreiac- 
tion, and to account for them in a satisfac- 
tory manner. 
It has been ascertained long ago, that pu- 
trefaction never takes place in those animal 
substances which contain only two or three 
ingredients, such as oils, resins, sugar ; they' 
must always be more complicated in their 
texture ; and, perhaps, in all cases, a mixture 
of two or more compound bodies is neces- 
sary for speedy decomposition. But how- 
ever complicated the animal substance may 
be, it does not putrefy unless moisture is 
present; for dry animal substances aie not 
susceptible of alteration. A certain degree 
of heat is also necessary. Animal bodies 
may be kept without decomposing for any 
length of time at the freezing temperature. 
In general the higher the temperature, the 
more rapid is the putrefaction, provided the 
heat is not great enough to reduce the ani- 
mal body to dryness. It has been observed, 
too, that putrefaction advances with more 
rapidity in the open air ; but exposure to the 
air is not necessary, though it modifies the 
decomposition. 
When these conditions are observed, and 
dead animal matter is left to itself, its co- 
lour becomes gradually paler, and its con- 
sistence diminishes ; if it is a solid part, such 
as flesh, it softens, and a serous matter sweats 
out, the colour of which quickly changes; 
the texture of the part becomes relaxed, and 
its organization destroyed ; it acquires a dis- 
agreeable smell ; the substance gradually 
sinks down, and is diminished in bulk ; its 
smell becomes stronger and ammoniacal. If 
the subject is contained in a close vessel, the 
progress of putrefaction, at this stage, seems 
to slacken ; no other smell but that of a 
pungent alkali is perceived ; the matter ef- 
fervesces with acids, and converts syr ip of 
violets to a green. But if the communica- 
tion with the air is admitted, the urinous ex- 
halation is dissipated, and a peculiar putrid 
smell is spread around with a kind of mpe- 
tuosity; a smell of the most insupportable 
kind, which lasts a long time, and pervades 
every place, affecting the bodies of living 
animals after the manner of a ferment, capa- 
ble of altering the fluids; this smell is cor- 
rected, and in a manner confined, by am- 
monia. When the latter is volatilized, the 
putrefactive process becomes active a second 
time, and the substance suddenly swells up, 
becomes filled with bubbles of air, and soon 
after subsides again. Its colour changes, the 
fibrous texture of the flesh being then scarce- 
ly distinguishable ; and the whole is changed 
into a soft brown, or greenish matter, of the 
consistence of a poultice, whose smell is 
faint, nauseous, and very active on the todies 
of animals. 'The odorant principle gradually 
loses its force; the fluid portion of the flesh 
assumes a kind of consistence, its col cur be- 
comes deeper, and it is finally reduced into* 
a friable matter, rather deliquescent ; which. 
