THE PROBLEMS OF THERAPEUTICS 175 



crobe which produces it, but serves again as a soil for another which 

 gives rise to a viscous fermentation. By the successive action of these 

 ferments a solution of sugar may produce, first, alcohol, secondly, 

 vinegar, and thirdly, ropy mucus. In this particular series each 

 microbe produces a substance injurious to itself but useful to its 

 successor. This is, however, not always the case because a cell may 

 produce a substance not only injurious to itself but injurious to other 

 cell, and alcohol in large quantity not only kills the cells of yeast but 

 kills other cells as well. Similar conditions occur within living organ- 

 isms where the cells composing the different parts are connected 

 together and pass on the products of their life from one cell to another 

 by means of the circulation of the blood and tissue juices. The secre- 

 tions of one part may be, and indeed generally are, useful to other 

 parts of the organism and so long as no part sins either by deficiency 

 or excessive action the whole organism maintains a condition of 

 health. But this is not always the case and health may be destroyed 

 by (a) excessive, (&) defective, or (c) perverted action of one or more 

 of the parts composing the body. 



But health is even more frequently destroyed by the invasions of 

 organisms from without. When these organisms fall upon an open 

 wound they tend to grow and multiply rapidly, they secrete ferments 

 and form poisons which enable them to destroy the tissues upon 

 which they have fallen, and then finding their way into the circula- 

 tion and being carried to all parts of the body they kill the animal 

 which they have attacked. 



One of the great problems of therapeutics then is to discover how 

 best to defend ourselves against the attacks of microbes. In Hogarth's 

 picture we see two methods by which this is done. The dog licks the 

 wound it has received and thus removes from it any pathogenic 

 organisms which may have lighted upon it. By insuring their absence 

 it renders the wound aseptic, and asepsis, which is another word for 

 excessive cleanliness insuring the absence of organisms, is one of the 

 great measures by which the triumphs of modern surgery have been 

 achieved. The treatment applied by the Good Samaritan to the 

 wounds of the traveler is somewhat different, for he pours in wine 

 the alcohol of which may hinder the germination of any microbes on 

 the wound and thus prevent them from producing sepsis. This 

 method, which in the hands of Lister has revolutionized surgery, 

 is termed antiseptic as distinguished from the aseptic method used 

 by the dog. There is no doubt that the aseptic method has got dis- 

 tinct advantages over the antiseptic method as applied to wounds 

 because any substance which injures or destroys microbes will like- 

 wise injure the living cells of that part of the body to which it is 

 applied. For this reason the aseptic method can only be employed 

 to a very limited extent against microbes that have already entered 



