1895.J MICROSCOPICAL JOURNAL. 315 



and obscure cases whereby we can establish a positive 

 diagnosis and prognosis. By the combined use of the 

 microscope, advanced chemistry and bacteriology, the 

 art of medicine of the past with its conjectures and 

 guesses, has risen to the more exact scientific basis of 

 the present, with its positive microscopical demonstra- 

 tions in diagnosis and prognosis. The improvement in 

 the microscope by opticians of late years, combined with 

 the discovery of the aniline dyes, have made it possible for 

 us to acquire a knowledge of the micro-organisms and 

 through its power to discover the microbic origin of 

 many of the infectious and contagious diseases. The 

 essential cause, without which the disease could not ex- 

 ist, has been discovered, classified and tabulated to the 

 number of over 70 distinct species of microbes, with 

 many of their specific diseases ("Eisenberg's Bacterio- 

 logical Diagnosis") a vast work far in advance of any- 

 thing previously attained in medicine as an art, and far 

 beyond our most sanguine expectation in medicine even 

 as a science — an accomplishment possible only by 

 patient microscopical investigation and close bacterio- 

 logical study. As the essential causes of many of the in- 

 fectious and contagious diseases have been discovered, 

 without which the disease cannot exist, no matter what 

 may be the predisposing factors, therefore a knowledge 

 of each particular essential cause enables a competent 

 observer in many obscure cases of disease to make a 

 positive diagnosis and prognosis by microscopical ex- 

 amination of sputa, blood, urine, feces, exudate, discharge 

 or whatever nidus contains the specific germ of the dis- 

 ease. We affirm that the micro-organisms do not change 

 their types, no matter what may be their environments; 

 they retain tlunr individuality of species, they do not 

 change from one species into another; for in the living 

 human body we only find the gonococcus in gonorrheal 

 pus, bacillus tuberculosis in tubercle, the comma ba- 



