8 



He states that " similar results have been obtained with 



" antigen prepared from strains of Pneumococcus Type I and 



" Pneumococcus Type III. Group IV pneumococcus antigens 



■ -how a precipitin reaction only within the limits of the 



" non-specific zone." 



Specific Soluble Substances. 



Dochez and Avery* have shown by means of the precipitin 

 test that pneumococci elaborate a specific soluble substance 

 during the first 12 hours of their cultural growth, i.e., at a time 

 when little or no death has occurred in the cultures. " This 

 " would seem to indicate that this soluble substance is not the 

 11 result of bacterial disintegration, but represents an actual 

 " extrusion of the cell substance into the medium during the life 

 " processes of the organism." 



They also found that similar substances were developed in 

 the animal body. For example, they inoculated a rabbit 

 intraperitoneally with 1 c.c. of the blood of a rabbit infected 

 with Type II, took blood from the heart at frequent intervals, 

 and tested the bacteria-free serum. Against the homologous 

 immune serum their results were : — before infection — , after 

 2 hours + , after 4 hours + + , after 6 hours + +> after 8 hours 

 + -f. Control tests with Type I serum were all negative. They 

 also found that Type II serum gave a marked precipitate with 

 the rabbit's urine taken at the end of 24 hours. In human 

 infections, they found that lobar pneumonia patients " have in 

 " their blood and more frequently in their urine a specific soluble 

 " substance of pneumococcus origin." The presence of a large 

 amount in the urine was to be regarded as an unfavourable sign. 

 Their general experience was that Type III strains formed " specific 

 soluble substance " more abundantly than Type II, and that 

 Type II formed more than Type I. These phenomena might be 

 associated with the property of capsule formation, which was 

 most developed with Type III, the capsules of Type II being 

 smaller and those of Type I still smaller. Their specific soluble 

 substance was not destroyed by boiling ; it was precipitable in 

 acetone, alcohol, and ether, and easily redissolved in water. 

 It did not dialyse through parchment and its immunological 

 reactions were not affected by digestion with trypsin. They 

 considered it "to be of protein nature or to be associated with 

 M protein." 



In connection with this subject, Cole's workf may be 

 mentioned on the neutralisation of antipneumococcus immune 

 bodies by infected exudates and sera. He found that in some 

 cases, though not invariably, fluid from the thoracic cavity in 

 cases of empyema following pneumonia reduced or abolished the 

 agglutinins and protective substances of the immune serum 



* Journ. Exper. Mr,/.. XXVI, p. 477. 1917. 

 f Journ. Exper. Med., XXVI, p. 453. 1917. 



