1901] MICROSCOPICAL JOURNAL. 75 
surroundings, they remain well. But give sucha person 
poor food or bad sanitary surroundings and see what hap- 
pens. The battle going on between the bacilli and the 
cells results in a victory for the bacilli. The cells die and 
the victorious bacilli spread havoc through the lungs. 
We, therefore, have a scientific proof of the sense of the 
old-time notions of the old-fashioned doctors, who taught 
the value of fresh air and sunshine, of good food and ex- 
ercise, of cleanliness and dry dwellings, and we find that 
the conditions of health which result from such good san- — 
itary conditions are, after all, among the very best pre- 
ventives against infection. 
That good sanitary environment, enhancing the gener- 
al health, is the best means of eliminating contagious dis- 
ease, is illustrated by a conversation which I have had 
within a week with the Director of the Hygienic Laboratory 
of the Marine Hospital Service, Dr. Rosenau, who has just 
returned, after a prolonged period of study and investi- 
gation in the Pasteur Institute in Paris. Upon inquiring 
as to the latest phases of scientific investigation and the 
trend of thought at this great intellectual centre, among 
other matters, he stated that there seems to have arrived 
a period of pause in bacteriology, or at least a spirit of 
inquiry as to the true relation of microbes to the diseases 
of which they have been considered the special agents. 
Dr. Rosenau’s statement is as follows: 
“We have lately been compelled to modify some of our 
notions of the causes of contagious and infectious dis- 
eases. After the brilliant discoveries by Pasteur and 
Koch, it was thought that the presence of the pathogenic 
microbe organism was like the bite of a venomous snake, 
surely poisonous. But now we know that there are other 
conditions beside the presence of the microbe necessary 
to produce disease. Many people go about with virulent 
cholera vibrio in their intestinal canal, yet they are not 
sick, have pneumonia, Why? Because their cells are 
