SOME ASPECTS OF THE IMMUNITY 



OUESTION. 



IT is well known that the refractary state of an organism 

 to diseases produced by bacteria or by toxines may be 

 either absolute or relative, further, the conception of im- 

 munity may include the whole organism or certain of its 

 constituent tissues and organs, and finally, the immune con- 

 dition may be natural or acquired. It is in connection with 

 acquired immunity that such an enormous literature has 

 accumulated since 1887. Previous to this date the methods 

 employed to confer immunity consisted either in the inocula- 

 tion of specific virus, in the preventive inoculation of specific 

 micro-organisms which were artificially attenuated by the 

 action of heat, compressed air or carbolic acid, as was prac- 

 tised by Pasteur, Toussaint, Chauveau, Arloing, Cornevin 

 and Thomas, or in the inoculation of absolutely inoffensive 

 bacteria which had lost their pathogenic property, a method 

 employed by Chauveau for anthrax and Hilppe for chicken 

 cholera. 



The preventive injection of sterile filtered cultures of 

 pathogenic bacteria marked an important advance in methods 

 for producing immunity ; and this was definitely demon- 

 strated about seven years ago by the researches of Salmon 

 and Smith (1) on hog cholera. In this country Wooldridge 

 (2) succeeded in protecting rabbits against anthrax by the 

 injection of filtered cultures obtained from a growth of 

 bacillus anthracis on a proteid (a nucleo-albumin) prepared 

 from the testis and thymus gland, a substance which has no 

 protective action before multiplication of the bacilli. His 

 experiments have been verified (3), and around this fertile 

 discovery considerable discussion has arisen. In the suc- 

 ceeding year, the bactericidal action of blood or serum was 

 discovered by Nuttall (4) and confirmed by many observers. 

 The advance in the study of immunity made by Wooldridge 

 may be gathered from his own words; as his discovery was 

 made at a time " when the few cases in which protection 



