120 Transactions of the Society. 



of a diseased patient is essential, and that such organism must be 

 so isolated from its surroundings, that its action may be tested by 

 experiment, and must produce the same or similar results when 

 allowed to act upon a healthy plant or animal. He could not 

 complete the chain, as at that time no methods of growing these 

 organisms in pure culture outside the body had been devised, 

 and animal tests were impossible ; but Koch, who succeeded in 

 making these animal tests, insisted that it was necessary, for 

 complete proof, to isolate the same organism from the experimental 

 case. 



Many of the earlier achievements in the history of bacteriology 

 we owe to the great botanist (John, of Breslau, and for long the 

 stimulus that he cave to tbose who were working under him or 

 were inspired by his example was chiefly instrumental in advancing 

 the study of this subject. From the time of Pasteur and Koch 

 onwards, however, this work has been taken over almost entirely, 

 not by the surgeon only, but by the physician also, who often, 

 with little training in botanical methods, but confronted by practical 

 problems of great significance to their art and to their patients, 

 have built up a new study which has revolutionized medicine, has 

 raised internal medicine from the position of a conventional art to 

 that of a great and living science, and has removed the reproach 

 that whilst surgery was scientific and progressive the physician 

 remained empirical and unenterprising. 



It is unnecessary to give an account of the numerous observa- 

 tions that were made, and controversies that were carried on 

 during this period — a period of great activity in the physiological 

 and pathological world. A few investigators were working away 

 steadily and quietly at the minute structure of tissues, and at 

 fungi and yeasts, and a still larger number were making sugges- 

 tions, forming hypotheses, elaborating theories and analysing the 

 work of this period, a vast mass of careful observation character- 

 izing the years between 1849 and 1859, when Pasteur took 

 up his famous work. The anthrax bacillus, the largest of the 

 pathogenic bacteria, was observed by Pollender in anthrax blood 

 in 1849, and again by Davaine and Payer in 1850, and in the 

 new search for the causes of disease this bacillus played a very 

 prominent part, the study of its life-history helping men to 

 crystallize their ideas as to the relation of micro-organisms to 

 disease. Davaine held that the virulence of an attack of anthrax 

 varied according to the number of the bacteria present in the 

 blood and although he was unable to furnish all the proof that 

 Koch later demanded, there can be little doubt that he was 

 satisfied that the anthrax bacillus was the primary cause of splenic 

 fever in animals. Edwin Klebs, a worker of great ingenuity 

 and industry — who has recently passed from amongst us, full of 

 years and held in honour by his fellows — devised a very striking 



