256 



THE PRINCIPLES OF IMMUNOLOGY 



intrathecal injections. The results so far obtained seem to be better 

 than when intraspinal injections alone are used. Frich also recom- 

 mends that all patients with positive signs and symptoms be given both 

 intraspinal and intravenous injections of serum. Large doses of serum, 

 both intravenously and intraspinally at frequent intervals apparently 

 do no harm, lower the mortality, prevent serious complications and 

 shorten the period of convalescence. 



Anti-pneumococcus Serum. Washburn, Mennes, Pane and numer- 

 ous other early investigators attempted to produce anti-pneumococcus 

 sera for the treatment of man, but their results were irregular and not 

 encouraging. An important advance in the production of anti-pneumo- 

 coccus serum was made when Neufeld and Handel in 1909 pointed out 

 that pneumococci can be divided into various immunological groups, 

 and that no curative properties can be expected from a given serum 

 unless it is homologous for the type that causes the infection. This 

 work has been confirmed and extended by Dochez and Gillespie, Cole, 

 Lister and many others. At present we recognize four groups. Groups 

 I and II are immunologically distinct groups, Group III is that of 

 the streptococcus or pneumococcus mucosus, and Group IV a heter- 

 ogeneous group of pneumococci which cannot be classified under the 

 other three groups. The following table, taken from Park ("The 

 Practical Application of Serum Therapy," Transactions of the Con- 

 gress of American Physicians and Surgeons, 1916, x, 118) gives the 

 group-incidence and mortality : 



* Presbyterian Hospital, Longcope. 



From this table it appears that about 30 per cent, of the cases of pneu- 

 monia and about one-third of the total deaths from the disease are 

 caused by Type I pneumococci. In the United States Cole claims that 

 75 per cent, of all pneumonia cases are caused by Types I, II and III, and 

 25 per cent, by Type IV. Lister, in South Africa, finds Type IV very 

 common among the negroes in the Rand. So far only Type I and 

 Type II sera have given encouraging results. The antigenic value of 

 Type III pneumococcus is exceedingly low, and that of Type IV vari- 

 able. From the more recent work of Raphael it would appear that 

 sera produced against various strains of pneumococci are in a sense 

 strictly monovalent and also that only virulent pneumococci are suf- 

 ficiently antigenic to produce antisera of distinct value. 



The sera against infection with Type I organisms have been used 

 extensively and appear to have given especially good results. The 



