president's address. 867 



been regarded as the wildest of speculations. Bacillus anthracis 

 is now universally recognised as the cause of splenic fever so 

 fatal amongst cattle, and is capable of being communicated to 

 other animals and to the human subject, as illustrated by the so- 

 called " Woolsorters' Disease." This Bacillus, compared with 

 others known, is of large size, the rods of which it is composed 

 being nearly one-fourth in diameter that of the red corpuscles of 

 the blood of the mouse. Koch, to whom we owe so much for 

 the study of this subject, has added to our conviction that the 

 Bacillus is the cause of the symptoms, as it is impossible to 

 suppose that an organism can develope in such enormous numbers 

 at the expense of the vital fluid as they are found by him not 

 only to be present in the spleen and other organs but that they 

 people the blood in the minute vessels of all parts. Koch found 

 that if putrid liquid is injected under the skin of a mouse it may 

 die in a short time as the result of the chemically tonic effects of 

 the products of putrefaction absorbed into the circulation ; if it 

 survive this primary disorder it may die in the course of about 

 two days of blood disease. The point of a lancet being dipped 

 into the blood of a mouse which has died in this way and the 

 skin of a healthy mouse being scratched with this envenomed 

 instrument, this second mouse dies with similar symptoms to the 

 first, and the same thing may be continued from mouse to mouse, 

 through any number. On making sections of the tissues of these 

 animals so diseased, they were found to be peopled with Bacteria in 

 enormous numbers, not so large as the Bacterium anthracis and 

 more delicate, one-eighth of the diameter only of the Bacillus 

 anthracis. This disease produced in the mouse is totally distinct 

 from pycemia, and thus it is shown by Koch that septiccemia may 

 exist as a deadly blood disease, caused by the development of 

 micro-organisms equally distinct from pycemia, and from the 

 chemically tonic effects of septic products. Koch found, beside 

 septiccemia, a local affection of the seat of inoculation, in the form 

 of a spreading gangrene. In this gangrene he found another 



