ITS PKACTICAL VALUE TO THE GENERAL PRACTITIONER. 9 



from the microscope and with no more complicated apparatus 

 than a test tube, to determine the presence and activities of 

 typhoid bacilli in the body; and thus, by a procedure scarcely 

 more difficult than the test for sugar in the urine, diagnose the 

 existence of enteric fever. The single example may serve to il- 

 lustrate the error of a prevalent opinion that bacteriology is 

 hardly accessible to the practitioner as an aid in his daily work. 



In this article I desire to mention a number of the practical 

 advances in bacteriology and to indicate how much of essential 

 value in the various fields they offer to the progressive physician. 

 Certain of these advances may never have a general use; others 

 are as yet very imperfectly developed ; improvements may be ex- 

 pected upon all ; yet we do our patients an injustice if we do not 

 avail ourselves of some of the present benefits. It is convenient 

 to group the bacteriologic advances under the general headings of 

 Etiology, Diagnosis, Prognosis and Treatment. In attempting 

 this, no excuse is offered for mentioning much that is trite to 

 many medical readers. 



Etiology. On referring to the causal relations of bacteria to 

 morbid conditions, we find that there is a large number of dis- 

 eases for which micro-organisms may reasonably be claimed as 

 the inducing factors; a considerable number for which certain 

 bacteria have been described as the etiologic agents, and until 

 within a very recent period but a very moderate number of 

 which definite bacteria have been satisfactorily established as 

 casual. Under this latter class we now have such prominent 

 bacteria as Koch's bacillus of tuberculosis, Eberth's bacillus of 

 typhoid fever, Klebs-Loffler's bacillus of diphtheria, Koch's spiril- 

 lum of cholera, Neisser's diplococcus (gonococcus) of gonorrhea, 



