INFECTIVE AND CONTAGIOUS DISEASES. 23 
the case in anthrax, the vessels tend especially to become 
blocked up where the current of blood is slow. So the Bacteria 
are marked in the thyroid body, and in certain parts of the 
kidney where stagnation of blood first .occurs, and in the lobules 
of the liver adjacent to the central venule. They tend to invade 
the epithelium of the blood vessels and are found in abundance 
in softening clots, and therefore perhaps are the direct agents in 
the production of thrombosis, and the softening of the clots in 
veins. The conditions essential to investigation of blood poison¬ 
ing in the loioer animals are peculiar, and require some experi¬ 
mental experience. Guinea-pigs are most unsatisfactory subjects 
for they die easily, and often without any apparent cause. 
Babbits also are not good, their variations in temperature are 
very uncertain. Bats and mice answer very well. But many 
inaccuracies of observation have resulted from neglect of the 
fact that different animals give varying results. Often we can 
produce disease very like the pyaemia of man. Caseous masses 
generally form at the seat of inoculation, and abscesses in various 
organs with a peculiar absence of true suppuration, the product 
being of a waxy character. On microscopical examination it 
shows the dumbbell form of Micrococci, and inoculation with the 
blood sometimes produces no effect, but often show inflammation 
of a local character, and sometimes acute disorder rapidly leading 
to death. In these latter the symptoms are of a febrile character, 
ecchymoses and abscesses being the most marked lesions. After 
death Micrococci may be found in the smaller blood vessels and 
especially in the patches of ecchymosis observable in the heart. 
These Micrococci are not generally in masses, but in chains or 
pairs, and are of large size. As has been found with other dis¬ 
eases, the blood is not the most likely fluid to communicate the 
disease by inoculation. Serum or fluid from a macerated portion 
of tissue will produce septicaemia with almost absolute certainty. 
The lecturer then gave a very hasty resume of KoclTs experi¬ 
ments, showing how at first he injected subcutaneously a large 
amount of decomposing fluid, when true poisoning resulted. 
But later he tried smaller quantities, and he found that after 
introduction of two drops many subjects remained unaffected, 
some sickened after twenty-four hours, death supervening in 
forty to sixty hours. He transmitted the disease thus produced 
in continuous series through seventeen inoculations. At first he 
could detect no Bacilli in the tissues and fluids, but he at length 
succeeded in detecting very minute forms by special means of 
illumination. They seem to enter the blood directly through 
the w r alls of the vessels, and to extend widely through the loose 
connective tissue. (Here the lecturer drew attention to diagrams 
of septicaemia Bacilli, some taken from specimens under Vr inch 
