CHAPTER II. 



METHODS OF EXAMINATION. 

 Chemical Reagents. 



21. The detection of micro-organisms in fluids and tissues was for 

 long a matter of extreme difficulty, and it has only been during late 

 years that, as the methods of lighting and staining objects were 

 improved, anything like uniform or satisfactory results could be 

 attained. 



Without oil immersion objectives with improved condensing and 

 illuminating apparatus, and without aniline colours, the vast field of 

 research now open to mycologists must have remained a terra incog- 

 nita. One can only wonder that so much had been done, when the 

 old methods are compared, or one should rather say contrasted, with 

 those at our command. In this chapter it must be our aim to detail 

 as fully and exactly as possible the various processes by which 

 micro-organisms may be prepared for examination in fluids, and in 

 moderately thick sections of tissues. 



Before commencing the description of the methods, it may be well 

 to consider what are the conditions under which these micro-organisms 

 are found, and the different media in which they have to be examined. 

 First, they may be present in some fluid or secretion from the body, 

 as in pus from an abscess, blood, sputum, fluid scraped from a fresh 

 surface of an organ, the fluid drawn from a vesicle or pustule, the 

 secretions or scrapings from the mouth, discharge from the urinary 

 passages, rectum, &c. ; in most of which fluids there is a certain 

 per-centage of albuminoid material, a factor which must be borne in 

 mind in connection with the mode of preparation of these fluids 

 for examination. Secondly, it may be necessary to examine certain 

 specially prepared fluids, in which micro-organisms are known to 

 flourish and multiply — fluid cultivating media. Thirdly, they may 



