590 THE PNEUMOCOCCUS 



is obtained with the micro-organism recovered direct from the infected person 

 while laboratory strains give negative results (Bezangon and Griffon). 



7. Precipitins. 



The serum of persons suffering from pneumonia and the serum of immunized 

 animals contain specific precipitins for filtered cultures of the pneumococcus. 



8. Immune body. 



The serums of pneumonia patients (Romer) and of vaccinated animals 

 (Neufeld and Handel) contain specific immune bodies (Sensibilisatrices) . 



SECTION IV. DETECTION, ISOLATION AND IDENTIFICATION 

 OF THE PNEUMOCOCCUS. 



I. Man. A. During life. To find the pneumococcus in a case of pneumo- 

 coccal infection the following materials should be examined : 



(a) Sputum. Collect the sputum with the ordinary precautions (p. 191) 

 and with a stout wire remove a small portion from the centre of one of the 

 rusty nodules. 



1. Prepare films for microscopic examination (vide infra, methods of 

 staining). 



2. It is hardly worth while to sow cultures with sputum since the other 

 organisms present will interfere with the growth of the pneumococcus. 



American observers have described several ways of isolating the pneumococcus 

 from sputum and saliva. Burger recommends sowing stroke cultures on glucose - 

 serum-agar (p. 53). The agar is prepared with 2 per cent, peptone water to which 

 2 per cent, glucose is added, and then made neutral to phenol-phthalei'n. On this 

 medium a characteristic culture of the pneumococcus is obtained in 18-20 hours 

 i.e. ring-shaped colonies with raised edges and depressed centres : by oblique vision 

 the ring is milky, the centre more transparent. 



3. Another portion is used for inoculation. Rub up a little of the sputum 

 with sterile distilled water [or normal saline solution] and inoculate the 

 emulsion into the root of the tail of a mouse. If the material be rich in 

 pneumococci the animal will die quickly. When the animal is dead aspirate 

 a little of the heart blood, or take a little of the medulla from one of the long 

 bones being careful to avoid contaminating it and sow tubes of agar and 

 broth. Incubate at 37 C. 



Inoculation for the purpose of identifying a suspected pneumococcus ought 

 always to be made into a mouse and not into a rabbit. Rabbits are not so 

 susceptible to the disease as mice, and indeed in some cases of pneumococcal 

 pneumonia the sputum contains pneumococci almost avirulent for rabbits 

 (Gamaleia). 



(b) The inflammatory exudate. Collect the exudate by putting a syringe 

 needle into an hepatized area (p. 198). The material must be examined by 

 microscopical examination and by inoculation. Bezan9on and Griffon prefer 

 to sow the exudate in a young rabbit's serum which has not been coagulated 

 and to inoculate mice with the culture obtained after incubating for 21 hours. 



(c) Pus and inflammatory exudates in other situations. The technique is 

 the same as for the material from the lung. 



(d) Blood. The pneumococcus is not found constantly in the blood of 

 persons suffering from pneumonia (Foa,. Talamon, Klemperer, Widal), though 

 it is usually present in severe cases. 



The examination in such cases should preferably be made about the fifth or sixth 

 day. When the disease is likely to prove fatal the pneumococcus can generally 



