258 THE PRINCIPLES OF IMMUNOLOGY 



subsequent doses are approximately 400 test-tube slants each. All the 

 injections are made intraperitoneally. Injections are given every two 

 weeks over periods of from four months to two years. One week after 

 the sixth injection a trial bleeding is made and thereafter at intervals of 

 two weeks, alternating with the biweekly injections. The sera possess 

 a high content of agglutinins and bacteriolysins and also exhibit a 

 marked therapeutic influence upon infected animals. Clinically the 

 serum is used in doses of 2.5 c.c., and injections made slowly. A ma- 

 jority of the cases have received one injection daily, but not infre- 

 quently two injections are given the same day. The injections are 

 continued until the temperature remains below 100 F. Of 538 cases 

 not treated, 244 cases died, the death rate being 45.3 per cent. Of the 

 175 similar cases treated with serum the death rate was 20.8 per cent. 

 In the ward in which the serum was employed the death rate during 

 the six weeks prior to the introduction of the serum treatment was 55 

 per cent. During the six weeks subsequent to the withdrawal of the 

 serum treatment, the death rate was 51 per cent. These results are 

 distinctly encouraging. McClelland has recently reported the results 

 in 322 cases of lobar pneumonia in soldiers at Camp Grant in which 

 treatment with fowl serum was given and concludes that the low 

 mortality (7.7 per cent.) together with the favorable modification of 

 clinical symptoms by the serum would seem to indicate the extension 

 of its use in pneumococcus pneumonia. Considering the fact that 

 these cases were in selected young men of military age, and that the 

 author does not give a comparative mortality among non-treated cases, 

 much of the value of this paper is lost. The serum has also been used 

 by Litchfield with great benefit in a series of pneumococcus meningitis 

 cases. Gray employed the Kyes serum in 234 cases of pneumococcus 

 pneumonia with a mortality of 16.8 per cent., whereas in similar cases 

 treated in the same way except that they received no serum, the mor- 

 tality was 63.6 per cent. Much laboratory and clinical work remains to 

 be done before any definite conclusive evidence as to the value of 

 polyvalent or antigroup sera can be drawn with any degree of safety. 

 Pneumococcus sera act in part by opsotiization of the cocci, thus favor- 

 ing phagocytosis. The standardization requirements of the Hygiene 

 Laboratory, Washington, call for a serum that shall protect white mice 

 against Type I pneumococcus only. It is felt by Ferry and Blanchard 

 and many others that a potent polyvalent serum is an absolute necessity. 

 These authors recently succeeded in immunizing horses with Types I, 

 II and III and some strains of Type IV. This serum in doses of 0.2 c.c. 

 protected mice against infection of Types I, III and IV organisms (ten 

 million M.L.D.). 



Anti-cholera Sera. While antisera against cholera have been pro- 

 duced by several investigators, the treatment of the disease with these 

 sera has not given the best of results. Metchnikoff, Roux and others 

 have prepared sera against the toxins of organisms cultivated in col- 

 lodion sacs. McFadyen used ground organisms. Kraus used the toxin 

 of the El Tor vibrio as antigen. This organism was obtained by 



