474 Pneumonia 



37.5°C. Ordinarily pneumococci seem unable to accommodate 

 themselves to a purely saprophytic life, and unless continually trans- 

 planted to new media die in a week or two, sometimes sooner. 

 Lambert found, however, that in Marmorek's mixture (bouillon 2 

 parts and ascitic or pleuritic fluid i part) the organisms would some- 

 times remain alive as long as eight months, preserving their virulence 

 during the entire time. 



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 avail- 

 able: 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 appUcation of iodine has been made, 

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

 from five to ten cubic centimeters of the blood permitted to drop 

 into a small flask containing about 100 cc. of appropriate media. 



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

 from the lung or pleura, a white mouse is usually selected as suitable, 

 the inoculation of a drop of the sputum, diluted with salt solution 

 if necessary, being made beneath the skin or into the abdominal 

 cavity. It is usually fatal in twenty-four hours. 



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. — The identification of the pneu- 

 mococcus may be a matter fraught with considerable difl&culty 

 when it makes its appearance in an unusual localization and espe- 

 cially when it lacks its characteristic lanceolate shape, its surround- 

 ing capsules and its occurrence in pairs. Under such circumstances 

 it is easily confused with the streptococcus and for the differentia- 

 tion recourse must be had to certain characters upon which much em- 

 phasis is laid by some authors, though others regard them lightly. 

 Here one should recall that a few authors even express the opinion 

 that the pneumococcus may be but the streptococcus temporarily or 

 permanently modified in small particulars by the mode of its occur- 

 rence. Rosenow* indeed, believes that he has succeeded in bring- 

 ing about such a mutation, between streptococci and pneumococci. 



To make the identification, therefore, advantage must be taken 

 of such peculiarities as are commonly supposed to belong to each 

 organism : 



* "Centralbl. f. Bakt. u. Parasitenk.," Orig. 1914, Lxxni, 284. 



