Page:The advancement of science by experimental research - the Harveian oration, delivered at the Royal College of Physicians, June 27th, 1883 (IA b24869958).pdf/52

 several characters. To the presence of some of these forms of the Micrococci are attributed many terrible varieties of disease, as pyaemia, erysipelas, internal suppurations. Some of these bacteria are found in the blood; they undergo stages of development and decay, and induce secondary changes in the tissues with which they come into contact.

Pasteur in his observations on splenic fever in animals and the manner in which the bacilli may be modified by successive germinations in proper fluids, has unfolded facts which will probably prove of immense value, but the interest has been eclipsed by the observations of Koch in reference to the bacilli of phthisis. That these bacilli are found in the expectoration of true phthisis has been established, and their presence has also been observed in the tubercle in the lung itself; while it is stated very positively that they do not exist in other forms of pulmonary disease as chronic pneumonia and chronic bronchitis; that in consequence phthisis is a disease directly communicable from one