INTRODUCTION xi 



organisms, beneficent and mischievous, has been revealed to 

 humanity ; and it is this new knowledge which has so largely 

 contributed to the diminution in disease and death at the 

 present day and which holds out to man the hope of a more 

 happy future. 



The micro-organisms inhabiting our bodies have set going 

 there a poison factory, which cuts short our existence, and by 

 secreting poisons which penetrate all our tissues, injures our 

 most precious organs, our arteries, brain, liver, and kidneys. 



Man balked of his full term of life feels himself unhappy and 

 is ready to accept any solution to the problem of gaining 

 happiness. And the progress of microbiology leads us to hope 

 that this science will one day liberate man from his fear of the 

 grave and permit him to attain the true object, the true 

 conclusion of life. 



It is time for bacteriological science to leave the laboratory 

 and the lecture theatre, and to take its place before the great 

 public, in order that its benefits may receive the widest and 

 readiest application. 



It was very natural for the creator of this " Library of 

 Scientific Philosophy " to apply to the Pasteur Institute for an 

 account of the actual position of science with regard to microbes 

 and toxins. Not only was the movement started from Pasteur's 

 laboratory and continued in the Institute bearing his name, 

 and still sheltering one of his most illustrious collaborators in 

 the person of Dr. Roux, but it is in this Institute that every 

 branch of microbiology is undergoing active study. To take 

 colloids and the physico-chemical laws which govern their 

 activity, we have at the Institut Pasteur studies on ferments 

 and fermentations as well as on the chemical processes which 

 lie at the root of life and of recovery from disease. In this 

 Institute also there are zealous workers in the field of infective 

 microbes and the means of combating them. 



Several laboratories are specially set apart for researches on 

 tropical diseases, and finally the Pasteur Hospital has been 

 created for patients suffering from all sorts of infectious maladies. 



If Pasteur were to see his Institute again, he would be 



