Vice-President’s Address. 25 
found in snails, in the bladders of fishes, in the vesicles 
of herpes or shingles growing in the epithelial cells, in 
' Paget’s disease of the nipple, in the livers of many rabbits, 
and in the proliferating cells of epithelioma, in molluscum 
jibrosum contagasiosum, and in a multitude of other con- 
ditions, show that these animal micro-organisms are associated 
with disease, and from what we know of vegetable organisms 
we must assume that in some cases at any rate they are 
the cause causantes of the disease. It does not require a 
great stretch of the imagination to see that protoplasm is 
protoplasm, whether it be animal or vegetable. We know 
that all cells feed, grow, multiply, secrete and excrete, that 
the most minute differences in appearance, in structure, and 
in composition, are accompanied by marked differences of 
vital manifestations, but we also know that cells which appear 
to be placed at extremes from one another, of cell life and 
structure, may give rise to phenomena which, with the 
methods at our disposal, we cannot discriminate one from 
another ; and we cannot therefore assume that the presence 
of these parasitic animal protoplasmic masses are merely 
accidental in any disease, though until we have proved their 
relations as causal agents to the disease, we must not be 
satisfied to accept them as such; let us apply to them the 
same searching tests that we have applied to vegetable micro- 
organisms, and as we continue to improve our methods of 
dealing with the latter, let us build up methods for eluci- 
dating the mysteries connected with the former. 
With all this, let it be remembered that there are all kinds 
of modified theories of disease, of immunity, and of vaccina- 
tion, that as yet we are dealing with isolated facts rather than 
with well-founded theories, and that it is our duty, though 
adding to the volume of facts, to keep an open mind as to 
their explanation. I do not wish for one single moment to 
discourage the seeking of explanations of facts and by facts, 
but I do wish to accentuate, as far as possible, the necessity 
that there is for us to set our faces against the building up of 
complicated theories on utterly inadequate foundation. We 
may rest assured that error will gradually be eliminated, 
facts will be sifted and rearranged, and new coigns of vantage 
