144 TRANSACTIONS OF THE PLYMOUTH INSTITUTION. 
comment on this, but I think our Antivivisection friends should 
consider whether their efforts do really tend to the better treat- 
ment of animals, leaving man out of the question. Do not the 
facts I have mentioned show that through these experiments of 
Pasteur he has been able to devise means to prevent animals 
suffering from anthrax — a very fatal disease — and that dogs who 
may be unfortunately bitten by a mad (relative) dog need not 
necessarily be destroyed, but can be treated so as to prevent the 
disease from developing ? 
The manner in which the attenuated virus acts in the way it 
does is not clearly understood. Yaccine lymph prevents small-pox 
by substituting a milder form of the disease, and so using up, it 
is supposed, the material in the blood which is favourable to the 
development of smallpox. 
Again, it may be that the blood-cells resist the attack of the 
fatal microbe by being gradually accustomed to its presence in a 
milder form, as persons may be accustomed to the use of opium 
or alcohol, until they can take what would almost immediately 
kill other persons. 
By degrees various living beings can be brought to tolerate 
quite different environments. Salt-water medusae can be made 
to live in fresh. Dr. Dallinger has shown that by gradations 
some bacteria can be brought to live in a temperature which, if 
they were exposed to it at the first, would be fatal to them. 
An important consideration from a health point of view is, 
to what extent these microbes will resist heat, and how long they 
will exist in water. Dr. Grancher finds that the moist -vapour 
stoves of MM. Geneste and Hersche are powerful enough to 
destroy microbes, although imbedded in mattrasses, &c, a 
temperature of 106° C. being easily obtained, the dry-air stove 
not being so efficacious. Dr. Percy Frankland found that 
Dr. Koch's comma spirillum of cholera was, in the purest form 
of distilled water, no longer demonstrable after the ninth day ; 
whilst in London sewage it was found in largely multiplied 
numbers after twenty-nine days. Organisms which do not 
naturally have water as a habitat when introduced into it are 
destroyed in large numbers, but some survive, and then a greater 
or less multiplication in their numbers subsequently takes place. 
With regard to the bacilli of anthrax, they are rapidly 
destroyed when introduced into London water ; but the spores, 
