340 . APPENDIX 



(3) Presence of spores, their appearance and position. 



(4) Whether or not the organism stains with Gram's method. 



(5) The character of the growth upon various media (gelatine, 

 agar, milk, potato, broth) ; the presence or absence of liquefaction 

 in the gelatine culture ; its power of producing acid, gas, or indol. 



(6) Whether it is aerobic or anaerobic. 



(7) Its colour in cultivation. 



(8) If it is a disease-producing organism under examination, 

 its effect upon the animal tissues and the course of the disease 

 should be observed. 



There are other points of importance, but the above are essen- 

 tial to a right conclusion. 



Diagnosis in Special Diseases : 



(i) Diphtheria. This disease may be bacteriologically diag- 

 nosed with a minimum of apparatus and equipment. By means 

 of a swab a rubbing from a suspected throat is readily obtained. 

 This may be examined by the microscope, or sub-cultured on 

 favourable medium. Blood serum is perhaps the best, but, as 

 Hewlett remarks, "If no serum tubes can be had, an egg may 

 be used. It is boiled hard, the shell chipped away from one end 

 with a knife sterilised by heating, and the inoculation made on 

 the exposed white surface; the egg is then placed, inoculated end 

 down, in a wine-glass of such a size that it rests on the rim and 

 does not touch the bottom. A few drops of water may with ad- 

 vantage be put at the bottom of the glass to keep the egg-white 

 moist. The preparation is kept in a warm place for twenty-four 

 to forty-eight hours and then examined." The examination, of 

 course, consists in staining and preparing for the microscope and 

 observing the form, arrangement, and characters of the organism 

 or organisms present. A small piece of the membrane may be 

 detached, washed in water, and stained for the bacilli. 



(2) Tubercle (Ziehl-Neelsen's stain, vide supra), 



(3) Typhoid {^Enteric Fever). 



Widal's Reaction. This diagnostic test depends upon the effect 

 which the blood of a person suffering from typhoid fever has 

 upon the Bacillus typhosus. The effect is twofold. In the first 



