PROPHYLACTIC VACCINATION 295 



also Fennel and Petersen have prepared lipovaccines. It was found pos- 

 sible to administer in a single dose 3000 million Shiga organisms, 3200 

 million Y type organisms and 2200 million Flexner organisms without 

 marked local or general reaction. In experiments with animals immune 

 sera can be prepared with much less difficulty when the organisms are 

 administered suspended in oil. The method ha& not as yet been given 

 sufficiently extensive trials in man to justify definite 'Statements as to its 

 efficacy, but from the experimental results obtained it appears to have 

 more promise than any of the other methods proposed. 



Vaccination Against Influenza. Vaccination against influenza was 

 practiced very extensively in the recent great epidemic. The contro- 

 versy over the etiological relationship of the bacillus of Pf eiffer has, in 

 our opinion, not been settled. The results of vaccination with this 

 organism might serve to settle in part the question as to the cause of 

 the disease, since a high degree of immunity to the disease following 

 vaccination, if interpreted in the sense of specificity, would indicate that 

 the organism employed is the exciting cause. The vaccines which have 

 been employed have been suspensions in salt solution, killed by heat. 

 In certain districts stock cultures have been employed, in others a cul- 

 ture of a strain or strains isolated during the epidemic has been used, and 

 in still others a mixed vaccine has been used composed of the bacillus 

 of Pf eiffer, the streptococcus, the pneumococcus, the staphylococcus and 

 other organisms. Reports of striking success following vaccination 

 have been numerous, including in particular the work of Duval and his 

 collaborators. In consideration of reports of this .sort the curve of the 

 epidemic has sometimes been overlooked. Reports of certain other 

 investigators have not been encouraging. McCoy states that " the gen- 

 eral impression gained from uncontrolled use of vaccines is that they 

 are of value in the prevention of influenza; but, in every case in which 

 vaccines have been tried under perfectly-controlled conditions, they 

 have failed to influence in a definite manner either the morbidity or 

 the mortality." At best the method must be regarded as still in the 

 experimental stage. 



Vaccination Against Other Diseases. Vaccines have been pre- 

 pared against scarlatina, cerebrospinal meningitis, tuberculosis and con- 

 taminated wounds. Examination of the statistics presented fails to 

 produce convincing evidence that vaccination against these conditions is 

 especially satisfactory. As time goes on, methods may be improved 

 and larger statistical evidence collected. 



