330 MEDICAL BACTEBIOLOGT 



a rusty color, due to presence of blood (rusty sputum) . The "pneu- 

 moeoccus" is readily seen in such material when stained by Gram's 

 method or with carbol-fuehsin and momentarily washed with alco- 

 hol, as lancet-shaped organisms with outer ends pointed and sur- 

 rounded by a clear area— the capsule. The capsule can be easily 

 stained by Welch 's method. ( See 27. ) 



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 is most susceptible and should be 

 inoculated subcutaneously. As a result of infection with this organ- 

 ism the animal dies quickly with a typical septicemia, the micro- 

 organisms being found in great numbers in the blood current. 



Bacillus pesUs. This micro-organism is frequently found in the 

 sputum, especially in the pneumonic form of the disease — for meth- 

 ods of detection see 105. 



Streptothrix hovis (aetinomyces). This organism has been occa- 

 sionally found in sputum and in such eases the peculiar morphology 

 of the colonies is well brought out by Gram's method. See 105. 



References, v. J. 114; Si. 245. See also various texts under 

 particular organisms. 



EXERCISE 102. EXAMINATION OF BLOOD. 



Collection. 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 recepta- 

 cles and hermetically sealed. For this purpose Sternberg's bulb is 

 excellent. The skin should first be sterilized by iise of corrosive sub- 

 limate or carbolic acid followed with alcohol. 



It is usually well in any case to make cover-glass smears at the 

 bed-side for microscopical 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 place a second cover-glass on 

 this; this flattens the drop of blood out into a thin film. Immedi- 

 ately and before coagulation 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 an- 

 thrax, blood or portion of spleen should be removed with least pos- 



