2 BACTERIOLOGICAL CHEMISTRY 



clicniistry is .somowJiat liko tliat of a. Jialf-fiiiisjKMl jig-saw 

 })Ti/zlo. (Sonio areas are nearly eojiiplele ; in otliers only 

 a few of the pieces have so far been fitted into place. 

 Quite recently the filling in of the area which includes 

 chemotherapy has been ^progressing rapidly as a result 

 of the development of the sulphonamide drugs, and a 

 reasoned account of their action can now be presented. 

 The subject of disinfection, however, is still in a nebulous 

 state ; we know a great deal about the necessary con- 

 centrations of disinfectants and the conditions for their 

 action, but very little as to how the observed results are 

 brought about. It seems probable that the present views 

 on the mechanism of chemotherapy may Avell be applied 

 to the action of disinfectants and antiseptics. 



The position of Immunochemistry, in this respect, 

 has improved considerably in the past decade and we are 

 at last able to understand something of what is really 

 happening during immunological reactions, although there 

 is much detail still to be filled in and much expansion of 

 our knowledge necessary. 



Our knowledge of the metabolic processes of micro- 

 organisms is perhaps the best developed part of the 

 whole structure and enables us to see the connections 

 between the modes of life of many different bacterial 

 types. Even here, though, we still know comparatively 

 little of the mechanism of the synthetic assimilation 

 processes. 



The scheme of treatment adopted in the following 

 chapters has been first of all to deal with the general 

 conditions which influence and determine the behaviour 

 or micro-organisms. The importance of the hydrogen 

 ion concentration and of colloidal phenomena is obvious, 

 as also is the part played by the enzymes on which almost 

 every stage of the life of the bacteria, yeasts and moulds 

 depends. Then follows an account of the different ways 

 in which micro-organisms obtain the energy and starting 

 materials for their growth and reproduction. The 



