Sessional_Paper_1904 — Page 652

543

·

In plague septicemia, bubonic and pneumonic manifestations are frequently met with.

In primary plague pneumonia, these complications rarely if ever occur. This disease, however, is accompanied by a certain amount of blood infection and be- comes septicæmic before death.

Primary plague pneumonias are usually fatal. Plague septicemias are not so lethal.

Considering the question of infection in plague from many points of view. there is much evidence in favour of the following :-

Plague septicæmias are occasioned in the majority of cases by infection through the gastro-intestinal tract. Rarely the infection effects an entry through a breach of continuity of the skin. Primary plague pneumonias are caused by "drop infection direct,

the B. pestis being inhaled.

77

On studying various epidemics of plague one is bound to be struck by the prevalence, during certain outbreaks of one particular variety of the disease. For instance, the pneumonic variety may predominate in one epidemic, the bubonic in another, or epidemics may be met with in which septicemic cases are most abundant. Again a frequent combination is the predominauce of septicæmic cases and cases with bubonic swellings, over pneumonic cases. We have, there- fore:

1. Epidemics of primary pneumonic plague.

2. Epidemics of prevailing septicæmic plague.

3. Epidemics of prevailing septicaemic plague with bubonic enlargements. 4. Mixed plague epidemics.

The factors upon which such outbreaks depend are by no means obvious. One is almost certain, from many points of view, that outbreaks of primary pneumonic plague, depend upon infection with a strain of B. pestis of extremely high virulence. During severe epidemics of primary pneumonic plague we find the plague bacillus fortified to the greatest degree of its pathogenicity.

An explanation of the occurrence of septicemic plagues with their various complications is difficult to give. Judging from what obtains in the case of the pathogenic actions of other micro-organisms, one is led to believe that the strain of the B. pestis calling forth pure uncomplicated septicemias is of higher viru- lence than the strain which not only calls forth a septicemia but gives rise to complications such as buboes and secondary pneumonias. The higher the viru- lence of the septicamia producing micro-organism the quicker is the fatal issue.

Before leaving the subject of pneumonic plague an important point must be mentioned. Plague pneumonia may occur alone, or it may be accompained by the formation of buboes in different parts of the body. There does not appear to be much connection between the occurrence of the pneumonia and the site of the buboes. In connection with this subject VOGES reports a inost interesting case of plague in which a combination of the different types of the disease was met with at one and the same period of the disease. This case began with pains in the neck, accompanied by redness in the fauces. Plague bacilli are said to have been found in great numbers in the mucus of the throat. For the first three days there was fever with other indefinite prodromuta; then there developed a typical case of plague with buboes, pneumonia and what he calls septicemia.

This case falls in with the views which I have brought forward. The case was septicemic and buboes were present. Had buboes been absent, the case would have been an excellent example of septicamia due to the B. pestis with pneumonia as a complication.

Again the presence of pre-existing disease, eg, tuberculosis, in the lungs of an individual suffering from septicemic plague, predisposes towards the occur- rence of secondary pneumonia. The plague bacillus finds a more favourable nidus for its development.

These views which I have expressed are original and somewhat in opposition. to the general consensus of opinion. I venture to put them forward, in the hope