184 Medical Bacteriology. 



1) Microscopically by staining, with a weak carbol-fuchsin, smears from the puru- 

 lent masses. If a very small bacillus is in large clumps, which fails to retain stain by 

 Gram's method, the evidence is strong that it is the influenza bacillus; the diagnosis 

 should be confirmed, however, by 



2) Cultures on blood agar. 



Animal inoculations are without effect. 



BACTERIUM PNEUMONIAE. 



The sputum of patients suffering from pneumonia is usually of a rusty color due to 

 presence of blood. The "pneumococcus" is readily seen in such material when stained 

 by Gram's method, or with carbol-fuchsin and momentarily washed with alcohol, as 

 lancet-shaped organisms with outer ends pointed and surrounded by a clear area the 

 capsule. The capsule can be easily stained by Welch's method. (See XXXVI.) 



This organism is also frequently found in the sputum of healthy persons and small 

 numbers may be detected by means of animal inoculation. The rabbit or mouse are 

 most susceptible and should be inoculated intraperitoneally. As a result of infection 

 with this organism the animal quickly dies with a typical septicaemia, the micro-organ- 

 isms being found in great numbers in the blood current. 



BACILLUS PESTIS. This micro-organism is frequently found in the sputum especially 

 in the pneumonic form of the disease for methods of detection see CX. 



STREPTOTHRIX ACTINOMYCOSES. This organism has been occasionally found in 

 sputum and in such cases the peculiar morphology of the colonies is well brought out 

 by Gram's method. See CX. 

 REFERENCES, v. J. 114; S. 245. See also various texts under particular organisms. 



EXERCISE CV1II. EXAMINATION OF BLOOD. 



For serum test (Widal reaction) the blood may be collected and dried (see below), 

 but in other cases where cultures are to be made the blood must be collected aseptically 

 in sterile receptacles and hermetically sealed- For this purpose Sternberg's bulb is ex- 

 cellent. The skin should first be sterilized by use of corrosive sublimate or carbolic acid 

 followed with alcohol. 



It is usually well in any case to make cover-glass smears at the bed-side for micro- 

 copical examination. These are best made as follows: Place a drop of blood about 

 the size of a pin-head on a perfectly clean cover-glass and then a second cover-glass on 

 this; this flattens the drop of blood out into a thin film. Immediately and before coag- 

 sulation can take place the two are drawn apart horizontally and the films allowed to dry. 

 (Cabot.) 



BACTERIUM ANTHRACIS. In case of animals dead of suspected anthrax, blood or 

 portion of spleen should be removed with least possible danger from infection or distri- 

 bution of bacilli and studied as follows: 



1. Microscopical examinations of blood or the spleen pulp of animals show (when 

 stained with Loeffler's methylen blue) large bacteria in chains (5 or 6 segments) pre- 

 senting the bamboo appearance. 



2. In hanging drop preparation large, homogeneous, immotile bacilli. 



3. Agar plate cultures should also be made and from the separate colonies subcul- 

 tures; the gelatin stab being especially characteristic. 



