190 The Microscope. 



5. The specimen is then again washed in water and after 

 becoming dry may be mounted in glycerine or Canada-balsam. 

 The bacilli alone are stained. By way of contrast the ground 

 may be stained with an aqueous solution of malachit-green if 

 fuchsin has been employed, or with Bismarck-brown (vesuvin) 

 if a violet dye has been employed. Then after washing and 

 drying the specimen may be mounted as above described. 



An amplification of 400-500 is sufficient for examination. 

 No immersion-lens or Abbe's condenser is needed. The advan- 

 tage of the method over that of Ehrlich consists in the substitu- 

 tion of muriate of alcohol for nitric acid. 



A much simpler method that we have tried repeatedly and 

 have found to work satisfactorily is that of Baumgarten, of 

 Koenighsberg, described in Birch- Hirschfeld's Pathological An- 

 atomy. 



The dry film, prepared as above shown, is stained by an al- 

 coholic solution of methyl- blue ; after washing in water the 

 preparation is immersed in Liquor Kali caustici. Thereby the 

 bacilli of tuberculosis are instantaneously discolorized ; all 

 other micro-organisms and the ground remain stained. The 

 specific bacilli appear as hyaline rods. — Western Medical Re- 

 view. 



ARRANGEMENT OF WORK-TABLE 



Rapidity and excellence of workmanship in mounting, as 

 in almost everything else of a mechanical nature, depends 

 somewhat on natural aptitude, but more on the proper and con- 

 venient arrangement of instruments and facilities, so that no 

 time is lost in putting the hand directly upon the desired instru. 

 ment or object. These, it is presupposed, are always kept in a 

 proper condition — the knives, needles, and scissors sharp and 

 clean, the cover-glasses and slips thoroughly clean and con- 

 veniently arranged, the wash-bottle filled with clean distilled 

 water, etc. Directly in front of the operator sits his reflecting 

 box ; to the left of which and close by is the bottle of cement. 

 In front of the reflecting box, but placed so that it will not in- 

 terfere with the light, is the vessel containing the objects to be 

 mounted. To the right is the case containing the slips, ringed 



