454 Pneumonia 



Virulence can also be retained for a considerable time by keeping 

 the organisms in the blood from an infected rabbit, hermetically 

 sealed in a glass tube, on ice. 



Bacteriologic Diagnosis. — It is usually unnecessary to call upon 

 the bacteriologist to assist in making the diagnosis of pneumonia. 

 If, for any reason it be considered necessary, three means are 

 available: i, the blood culture; 2, the inoculation of animals 

 with the expectoration; 3, the cultivation of the organism from the 

 expectoration. 



1. To make the blood culture, the elbow is encircled with a band, 

 the skin washed and after an application of iodine has been made, 

 a hollow needle is introduced into one of the distended veins, and 

 the blood permitted to drop into a small flask or tube of appropriate 

 media. 



2. To inoculate an animal with the sputum, or with fluid drawn 

 from the lung or pleura. A white mouse or a rabbit can be selected 

 as suitable. Both animals are so susceptible that the introduction of 

 one drop beneath the skin is usually fatal in twenty-four to forty- 

 eight hours. 



Caution must be exercised in using this means of diagnosis, how- 

 ever, as the pneumococcus sometimes occurs in normal saliva, 

 and is a common associated organism in tuberculosis and other 

 respiratory diseases. 



3. The recovery of the organism from the sputum can be accom- 

 plished by stroking appropriate media with a platinum wire dipped 

 in the sputum. The characteristic colonies can be picked up and 

 transplanted as soon as they appear. 



Identification of the Organism. — Wadsworth* has been able to 

 show that agglutination reactions can be obtained by concentrating 

 the pneumococci in isotonic solution and adding the serum. The 

 method does not seem easily applicable for diagnosis. Neufeldf and 

 Wadswortht have also found that when rabbit's bile is added to a 

 pneumococcus culture so as to produce lysis of the organisms, the ad- 

 dition of pneumococcus-immune serum to the clear fluid so obtained 

 results in a specific precipitation. This seems to have little practical 

 importance, however, for purposes of diagnosis. It is, however, of 

 some importance in assisting in the recognition of the pneumococcus 

 and differentiating it from the streptococcus, for when the latter 

 organisms are similarly treated no precipitate takes place. 



Buerger! found that all pneumococci, irrespective of source, 

 were agglutinated by pneumococcus-immune serum, that such serum 

 was capable of agglutinating various pyogenic streptococci, certain 

 atypical organisms, and certain strains of Streptococcus mucosus 

 capsulatus. The sera of pneumonia patients varies in its power to 



* "Jour. Med. Research," 1904, x, p. 228. 



fZetschrift fur Hygiene," 1902, xi. 



t Loc. cit. 



§ "Jour. Exp. Med.," Aug. 25, 1905, vn. No. 5. 



