INTRODUCTION 



WE live in a world that is teeming with life. From the 

 earliest times of man that life has been studied and 

 the observations recorded. Thus there has slowly come to 

 be a considerable accumulation of knowledge concerning the 

 various forms (morphology) and functions (physiology) of 

 organised life. This we call the science of biology. It has 

 for its object the study of organic beings, and for its end the 

 knowledge of the laws of their organisation and activity. 

 Slowly, too, in the midst of this gradual accumulation of 

 facts, we begin to see incoherence becoming coherent, chaos 

 becoming cosmos, chance and accident becoming law. 

 Further, the contemplation and comprehension which built 

 up the edifice of modern biology is assuming a new relation- 

 ship to practical life. Biology can no longer be considered 

 only as an academic occupation or as a theoretical pabulum 

 upon which the leisured mind may ruminate. With rapid 

 strides and determined face this giant of knowledge has 

 marched into the arena of practical politics. The world is 

 opening its eyes to a reality which it had mistaken for a vision. 

 This application of biology to life and its problems has in 

 recent years been nowhere more marked than in the realm 

 of bacteriology. This comparatively new science, associated 

 with the great names of Pasteur, Koch, and Lister, furnishes 

 hideed a stock illustration of the applicability of pure biology. 

 ''Turn where we will, we shall find the work of the unseen 

 hosts of bacteria daily claiming more and more attention 

 from practical people. Thus biology, even when clothed in 

 the form of microscopic cells, is coming to occupy a new 

 place in the minds of men. " Its evolution," as Professor 



