MEMOIRS OF A VETERINARY SURGEON. 
201 
mineral chameleon, permanganate of potash, or soda in pure 
water, and is of a reddish purple shade.” 
The above is extracted from an essay read by Dr. Smith 
before the Royal Institution of Great Britain, March 25th, 
1859- The author had established the correctness of his 
theory by numerous experiments made upon Snowden, Mont 
Blanc, St. Bernard, near Milan, on the open sea, in London, 
Manchester, dwelling-houses, pigsties, &c. In a letter kindly 
addressed to me to-day, the author says, “ I have not yet 
ascertained the average for stables, but have found some of 
them three times more unwholesome than others, or in 
other words, giving out into the air three times more un¬ 
wholesome matter. The substance used for testing the air 
and estimating the amount of oxidisable matter is an alka¬ 
line permanganate. It has a deep colour, and the amount 
of the impurity is judged of by the amount of the solution 
from which one hundred cubic inches of air will remove the 
colour. There are other and similar substances capable of 
being thus employed. I hope soon to publish three or four 
hundred experiments with it. I do not think exact observa¬ 
tions will be made by any one except a chemist; but I believe 
comparative observations for daily guidance may be made by 
those who are not acquainted with chemistry.” 
The great difficulty I have always felt has been in seasons 
of hot sultry weather, when the thermometer has stood from 
80° to 90° in the shade. How very pleasant is a breath of 
fresh, cool air to a poor, suffering patient burnt up with in¬ 
ternal fever ! You can judge by his very looks how grateful 
he feels to you when you can provide it for him. It is the 
instinct of nature speaking to us, and it is our duty to listen 
to her and help her as much as we are able. I hold it to 
be a great responsibility to have the life of a valuable animal 
placed entirely under our care, scarcely second to that of the 
man whose comprehensive intellect metes out the dose that 
w T ill certainly save or jeopardize a human life. How often 
have 1 had the front of the sick-box degged with salt and 
cold water on such occasions, aye, the walls, the roof, and 
even the floor itself, in the hope that evaporation taking 
place it would to some extent lower the temperature. With 
this I have conjoined the waving and shaking of sheets to 
agitate the air. But I now employ another means, which, 
after many anxious trials, I have to some extent found to be 
successful, but which is still capable of further improvement. 
XXXIII. 
27 
