260 Proceedings of Royal Society of Edinburgh. [sess. 
acetic acid proves a germicide. Therefore the product of its own 
life-history plays the part of a powerful toxic agent on the further 
life of the bacterium. 
From Baginski’s researches may we not draw the inference that 
in certain contagious diseases “ the turning-point for the better” 
is due to products formed by the microbes, which act detrimentally 
upon any further growth and development. 
In a paper read before L’Academie des Sciences on October 26, 
1886, Pasteur stated that “a large number of microbes apparently 
give rise, in the media where they grow, to substances which have 
the property of opposing their own growth.” And again, “ might 
it be that rabies virus was made up of two distinct substances, the 
one living and capable of multiplying in the nervous system, the 
other not living, but capable still, when in suitable proportions, of 
arresting the development of the first ” % 
(c) The Microbe (?) of Hydrophobia. 
M. Galtier of Lyons found that salicylic acid injected hypo- 
dermically was quite inefficient in preventing the development of 
hydrophobia. 
In a communication to the International Medical Congress 
(Copenhagen meeting), held on August 11, 1884, M. Pasteur stated 
that “ the process for isolating the microbe is still imperfect, and 
the difficulties of its cultivation outside the bodies of animals 
have not yet been got rid of, even by the use, as pabulum, of fresh 
nervous matter.” Then, again, in a paper read before L’Academie 
des Sciences on February 25, 1884, Pasteur stated that in micro- 
scopical sections of a rabid medulla there are numerous minute 
granules, “ suggesting the idea of a microbe of extreme tenuity, in 
shape neither a bacillus nor a diplococcus ; they are like simple dots.” 
From the researches of Pasteur, we note that the microbe of 
rabies has a very different life-history from other micro-organisms. 
The principal seat of the virus is in the central nervous system; 
even after the injection of the poison into the blood system, “the 
spinal marrow is the region first attacked, the virus locating itself 
and multiplying there before spreading to other parts.” Therefore, 
the virus of rabies does not reside in the blood , — which accounts for 
Cal tier’s failure with salicylic acid. 
