Vice-President’s Address. 141 
others the microbe. When the former was the case the 
leucocyte took the microbe into its interior and destroyed it 
by a process analogous to digestion in unicellular organisms, 
and this power led to these cells being named Phagocytes, 
and the process Phagocytosis. On the other hand, when 
the microbe was victorious it killed or paralysed the 
leucocyte, probably by the action of the toxines produced by 
it. The inflammation which occurred at the part thus 
became a beneficial process, which had, as one -of its most 
essential elements, the local supply of an additional number 
of leucocytes. In addition, however, to a local increase of 
leucocytes, it has been found that in many instances there 
was an appreciable increase in the number throughout the 
blood generally, from which it was inferred that the toxin 
locally produced had a stimulating effect on the organs 
forming white blood-corpuscles. That this is so has been 
abundantly proved by a similar effect being produced when 
toxines, apart from the microbe producing them, were in- 
jected. Not only has this been shown to be the case, but, 
in addition, it has been shown that the introduction of 
antitoxic serum has in many instances a similarly stimulat- 
ing effect upon these organs. In many cases the influence 
which the antitoxic serum has in stimulating and increasing 
the fighting power of the leucocyte can be demonstrated. . In 
no case, perhaps, is this better seen than in the case of 
diphtheria, where, as a result of antitoxic inoculation, the 
leucocytes accumulate at the seat of the local invasion, and 
actively and successfully destroy the diphtheria bacilli, thus 
preventing the further development of toxin. 
In various other instances the proportion of leucocytes 
in the blood is an indication of the virulence of the toxin 
being produced in the course of a disease of microbic origin. 
For it has been found that, as a rule, if the toxin be very 
virulent no increase of leucocytes takes place, the toxin 
having a paralysing effect upon their production. It thus 
follows that a toxin of a moderate measure of virulence 
stimulates the natural fighting power of the leucocyte, while 
a higher measure of virulence renders it helpless and 
passive. 
VOL. XIII. L 
