28 DEVELOPMENT OF THE GERM THEORY. 



cannot leave without dissolution of the cell, it remains within its 

 narrow confines, and is destroyed either by some as yet unknown 

 chemical substance or dies from starvation. In either event the 

 vitality of the cell is not impaired, and the microbe disintegrates 

 or disappears. If the conditions for the growth and development 

 of the microbe in the protoplasm of the cell are more favourable, 

 intra-celiular multiplication of the microbe takes place ; the pto- 

 maines which are eliminated produce coagulation-necrosis in the 

 protoplasm ; the cell disintegrates ; and the intercellular culture is 

 liberated in an active condition. 



In cases of unsuccessful warfare of the phagocytes against 

 invading micro-organisms, the mechanical obstruction composed 

 of emigration corpuscles and embryonic cells is broken down ; 

 and the rapid increase of micro-organisms at the seat of inflam- 

 mation gives rise to extensive local and often general infection. 

 From a practical standpoint, it can be said that all therapeutic 

 measures which influence favourably the process of phagocytosis 

 in the broadest meaning of this word are calculated to exert a 

 potent influence in arresting or limiting the infective processes. 

 For example, the application of counter irritants around an 

 inflamed centre would cause an active immigration of leucocytes, 

 and it is probably upon this that their well-known usefulness 

 depends. 



In addition to this vis inedicati-ix fiaturce just pointed out, we 

 can do a very great deal for our own protection, and the old 

 adage that prevention is better than cure points out to us the lines 

 upon which we should proceed. It is in the field of preventive 

 medicine we have done most and have still much to do. The 

 personal care of the health ; the notification and isolation of 

 disease ; the disinfection of disease areas ; the preventive and 

 curative inoculations ; the inspection of our food supplies ; the 

 drainage and ventilation of our soils and houses ; the establish- 

 ment of laboratories in connection with our PubHc Health Depart- 

 ments for studying the history of infectious diseases in man and 

 animals ; in fact, the improvement of every condition of life leaves 

 a large field still open for our work. 



The author of Civilisatiofi : Its Cause and Cure, says : — " If 

 the extent of the national sickness is such that we require 23,000 



