28 BIOLOGY OF PNEUMOCOCCUS 



venously to pneumonia patients, and favored large doses. In the 

 same year, a few months earlier as a matter of fact, Washbourn 1487 

 had injected ponies with a culture of exalted and constant viru- 

 lence, and after proving to his satisfaction the favorable action of 

 the serum on rabbits, administered it to six pneumonia patients. 

 All, although severely ill with the disease, recovered. He made an- 

 other advance by standardizing the serum, and set as a unit the 

 smallest amount of serum which, when mixed with ten times the 

 least fatal dose of pneumococci and injected into the peritoneum, 

 would bring about the survival of the test rabbit. Washbourn em- 

 phasized the necessity of early treatment and advised injections of 

 at least six hundred "units" twice daily. By himself, and in the 

 following year with Eyre, 876 he examined immune horse serum for 

 protective properties, and concluded that there was no parallelism 

 between agglutinative, bactericidal, and protective power. In their 

 papers ( 1899-1900), 375,377 these two authors gave further reports 

 on the results of potency tests made on antipneumococcic serum, 

 including two samples of Pane's product. By this time they had 

 modified their method, and now injected the serum intravenously 

 and then the culture intraperitoneally into rabbits. The serums, in 

 one cubic centimeter amounts, usually protected rabbits against a 

 thousand or more fatal doses of pneumococci, but in a few in- 

 stances failed to protect against strains from another source, ow- 

 ing, as we now know, to a lack of type correspondence. 



Summary 

 At the turn of the century the results of Pneumococcus investi- 

 gations could be inventoried as follows: Pneumococcus was ac- 

 cepted as the causative agent in lobar pneumonia ; it could be 

 grown outside the body, and some of its habits and metabolic ac- 

 tivities were becoming known ; Pneumococcus or its products were 

 found to raise the resistance of some experimental animals to ho- 

 mologous infection ; these animals could be made to yield a serum 

 capable of conferring passive protection on vulnerable or stricken 



