NOTES ON MICRO-ORGANISMS. 33 
One of Pasteur’s most interesting experiments has a distinct 
relation to the foregoing matter. He found that birds were not 
susceptible to Anthrax virus, and, presuming that it was from the 
high blood temperature, 105 degrees Fahrenheit, he tried the 
experiment of reducing the temperature of a fowl to 98 degrees 
Fahrenheit, by placing the feet in cold water. Under these con- 
ditions it was inoculated with Anthrax virus, and died in twenty- 
four hours. Another fowl, so inoculated and assisted back to its 
normal blood-heat by exposure to a temperature of over 100 
degrees Fahrenheit, recovered completely. 
One of the most important points connected with researches on 
pathogenic organisms, is to discover methods for weakening or 
attenuating the virus. Pasteur has, we know, been exceptionally 
successful in this line. In the case of splenic or anthrax fever 
guinea pigs were employed, and it appeared that when these were 
young the virus had not so much effect as on old ones, and in the 
former case had lost power. ‘The full strength of attenuated virus 
would be restored by cultivation in guinea pigs of successive ages. 
starting with young ones and ending with old. Many micro- 
organisms have their virulent properties reduced by exposure to 
air or oxygen gas. 
Public interest has been gradually, but is now fully, awakened by 
Pasteur’s splendid research in connection with hydrophobia, com- 
menced in 1880 and now apparently brought to a successful issue. 
So much notice of this work has been taken by the daily press 
that the main facts are fresh in our recollection. Some of the 
most important departures in the earlier days of this research 
were :—inoculating with brain substance from animals that had 
died of rabies, by introduction into the brain of living animals, 
and the attenuation of the virus by cultivation in rabbits. 
There is little doubt that the spores of some of the pathogenic 
Bacteria have nearly the same resisting powers as those of 
commoner organisms. The spores of Bacillus anthracis, for 
instance, can stand a boiling heat without destruction. 
Whilst the tissues are in a thoroughly healthy condition they 
are probably well able to resist the influence of organisms, other- 
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