FORTIFYING AGAINST DISEASE. 37 



isolated from cultivations of the Bacillus anthracis albumoses 

 which were found by Hankin to produce immunity from the dis- 

 ease when injected into the "body. Possibly under the influence 

 of Hankin, certainly later in the year, the important researches of 

 Fraenkel and Brieger on the toxalbumins of diphtheria, typhoid 

 fever, cholera, tetanus, etc., were published. Thus, just as in the 

 case of many remedies used for centuries in the shape of powders, 

 extracts, decoctions, infusions, tinctures, etc., active principles have 

 ultimately been discovered by chemists, it was now found that 

 out of the material used for the last ten years by Pasteur and his 

 school, it ivas possible to isolate some active products of definite 

 composition, to which the lymphs or " vaccins " owe their prophy- 

 lactic and curative properties. Such was the state of science 

 when, in the course of last year, it was announced that Koch had 

 found the means of curing phthisis by inoculation. All minds 

 were to a certain extent prepared for such an announcement ; yet 

 the fact that one of the greatest scourges affecting human kind 

 had at last come within the pale of treatment has created im- 

 mense sensation. The little that is known of the treatment and 

 of its effects seems to point clearly to the fact that Koch is using 

 some of the chemical products which have just been discussed, 

 and therefore there is good reason to expect that a certain amount 

 of success will attend the method. The results of previous experi- 

 menters show, however, that it would be wrong to hope too much 

 from a system which has always been attended with a certain pro- 

 portion of failures. 



I have carefully avoided in this eocpose to enter into many de- 

 tails, some of which are of great importance, in order that you 

 should be able to follow the main line of observations and 

 thoughts which have led to the recent discovery. I will there- 

 fore not attempt to discuss on what basis vaccination, essentially 

 prophylactic in principle, may become a curative method when 

 the modified virus answers certain requirements. There is a very 

 distinct connection between these two methods of treatment.* It 

 may, however, be interesting to consider for a moment the meth- 

 ods which the knowledge of pathogenic organisms has introduced 

 in medicine. 



These methods can be subdivided into three classes : (1) The 

 preventive, (2) the protective, (3) the curative. They have all some- 

 thing in common, and yet they all differ, as will be seen in the 

 following brief enumeration : 



1. The preventive method consists in destroying or attenuating 



* For explanation as to the mode of action of the products used in vaccination, see 

 Lauder Brunton's lectures on Chemical Structure and Physiological Action, especially 

 Lecture II (British Medical Journal, vol. i, 1889, p. 13S9). 



