238 BACTERIA. 



showing a greenish florescence. In odour it resembles elder yeast or leaven, 

 combined with a sweet aromatic admixture, such as honey. If slowly 

 heated, the smell of yeast gives way to an agreeable odour resembling 

 fruits ; on further heating, the smell becomes like that of fresh bread 

 crust," but without the acid fruit odour. If the heating of the material is 

 continued, "the smell assumes the . empyreumatic character exhibited by 

 burning albuminous matter and carbonizing horny substances. Only an 

 extremely small quantity of ash (under I per cent.) was obtained. The 

 liquid shows a neutral reaction. " It was found to contain a small quantity 

 of mucine, indicated by a turbidity on the addition of dilute acetic acid, 

 which is increased on the addition of potassium ferrocyanide, indicating the 

 presence of albumen. Peptones are present in considerable quantities. 

 There is a slight reducing action obtained when the fluid is heated with 

 Fehling's solution ; there was no reaction with acid bichromate of potassium, 

 so that acids and ptomaines are absent ; but it was assumed, as would now 

 appear incorrectly, that toxalbumens, or albumoses, globulins, or enzymes 

 must be the substances to which the material injected by Koch owes its 

 special properties. 



Any description of the lymph other than that given by 

 Koch himself must be the result merely of guess-work, but 

 even guesses will sometimes afford indications as to the lines 

 on which researches are at present being carried out, not 

 only in connection with tuberculosis, but with several other 

 most deadly and wide-spread diseases. The peculiarity of 

 this method of treatment is, that it is not known to pro- 

 tect against an attack of tuberculosis, though Koch states 

 that he hopes his guinea-pigs will be protected from future 

 attacks ; it is used solely as a therapeutic agent to check or 

 stop the disease after it has once obtained a foothold in the 

 body. It is thus in principle more like Pasteur's inoculation 

 against hydrophobia, for the inoculation is made after the 

 patient has been inoculated with the disease virus ; and it is 

 also similar in certain points, though the principle is different, 

 to the protective inoculation obtained by Hankin, who, by 

 means of albumoses obtained from anthrax cultivations, has 

 been able to produce immunity against anthrax, though not to 

 cure, after that disease was once induced ; and that Dr. Cart- 

 wright Wood and I carried on with the pyocyanin products 

 in rabbits, to tide them over an attack of anthrax the bacilli of 

 which were introduced into the subcutaneous tissue shortly 

 before, or immediately after, the injection of the pyocyanin. 

 We, however, considered that the pyocyanin had not acted 

 directly on the anthrax bacillus, but that it acted by stimu- 

 lating the cells ; whilst Koch's " lymph" acts (i) by destroy- 

 ing the tuberculous tissue, and rendering it unfit for the 



