634 
Proceedings of the Royal Society 
odour. Under the microscope, it was seen to consist chiefly of 
amorphous matter, of cells like the spores of mucedo, and of blood 
corpuscles, — these, except in form and size, but little altered ; — no 
crystals were visible. It imparted to water only a very faint, just 
perceptible, brownish hue, as seen after flltration and separation of 
suspended particles. The water had a strong alkaline reaction, 
but was almost tasteless. 
A clot of blood — to mention another instance — which had been 
boiled only ten minutes, kept the same time, offered nearly the 
same results. It escaped the putrefactive change ; mould formed on 
it, which, after more than a year, was of various colours, bright red, 
white, and black — changes of colour, it may be conjectured, owing 
to the different states of the vegetation. 
Is the change which meat and blood undergo after exposure to 
a boiling temperature, as described, in any way analogous to that 
which vegetables experience wdien converted into peat? — a conver- 
sion which appears to take place only at a comparatively low tem- 
perature — below that favouring rapid decomposition ; for I am not 
aware of any peat-formation having ever yet been discovered in 
progress within the tropics or in any locality the mean annual tem- 
perature of which is above 60° of Fahr. 
4. On the Influence of Sulphurous Acid and Acetic Acid in arresting 
Putrefaction. 
From time to time I have made some other experiments on meats 
chiefly with a view to their preservation. The first instituted were 
with sulphurous acid, of which I have given an account in a volume 
of “ Researches,” published in 1839, The second were on vinegar, 
the results of which are there also described.* The sulphurous acid 
had previously been employed in arresting the fermentation of the 
more delicate white wines. I found it to arrest the putrefaction 
equally well of animal and vegetable substances, and so preserving 
them as to render them not unfit for use as human food. Trials 
with vinegar and dilute acetic acid gave somewhat similar results, 
so far as the immediate arrest of putrefaction was concerned ; but 
it did not, like the sulphurous acid, so alter the character of the 
Researclies Anatom, and Physiol, vol. i. 
