NOTES 
129 
These disease-producing germs the bacteriologist 
soon came to know very well as he grew them in the 
safe purlieus of his laboratories and found out the 
various ways in which they were able to work havoc 
in the delicate mechanism of their earth-neighbor, 
man. Thus the nature of disease became clearer and 
the problems of its prevention and cure definite and 
precise. 
BARRIERS OF THE BODY. 
The healthy human body is safe-guarded in many 
effective ways against the entrance and continued life 
of bacteria and allied organisms. The tough skin 
affords a most impregnable barrier. The nose and 
throat and the tubes leading to the lungs are protected 
with various mechanisms barring the way to many 
germs which dusty air bears in every breath. The 
complex chemical processes in our digestive apparatus 
which convert our\food into building material for 
brain and muscle spell death to the myriads of bac¬ 
teria with which our uncooked foods are mingled. So. 
altogether, our life among bacteria, even those of the 
deadly sort, is usually exposed to little hazard. 
But when the best is said, these minute inciters of 
disease do now and then win their way to the intimate 
recesses of our bodies, producing serious results. The 
measure of their ravages is found in the tables of the 
statisticians, which show that a large proportion of 
all who die fall victims to these invisible foes, and 
that, too, at an age when life holds out its brightest 
promise. 
