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distinctly manifested. (2) The plasmodial stage, where there is 
excessive nutrition or excessive stimulation, and where there is 
latent formative tendency, which comes into play on the removal of 
excessive stimulation. (3) The encysted stage, where the formative 
activity is a more prominent feature than the nutritive. In normal 
tissues under normal conditions, the metabolic processes balance one 
another. Under the influence of irritation, this balance is lost ; 
there is first, excessive nutritive activity, corresponding to the 
amoeboid stage, in which the process of aggregation is well marked, 
as instanced by cloudy swelling of the cells of various organs during 
the early stages of specific infective fevers. If the irritation is 
continued, this is followed by greatly increased nutritive activity, 
or rather digestive power, which is found in the plasmodial stage. 
In both these forms, if the irritant be excessive, complete aggregation, 
followed by disintegration, takes place; while, if irritation be not 
excessive, formative activity is evolved, and we have a tissue 
formation corresponding to the encysted stage of the cell. In our 
paper we have attempted to illustrate these processes by a description 
of the phenomena observed on a septic granulating surface, in an 
abscess, in actinomycosis, and in tubercle. 
From Marshall Ward’s recent researches on the mode of repro- 
duction in certain cellular organisms, it appears that it is possible 
for a parasitic fungus to reproduce its like without the direct aid of 
a sexual process, the necessary stimulus to multiplication being sup- 
plied by the highly organised proteids, derived from the tissues of 
its host, which in their turn are also stimulated into proliferation. 
Applying this to the case of cells in an animal, it would appear that 
the stimulus applied by the presence of micro-organisms, or their 
chemical products, acts in a manner comparable to the action of the 
male element upon the ovum in setting up segmentation. There is 
thus a reappearance of excessive reproductive activity without the 
process being re-initiated ab ovo. Cell proliferation may be set up 
by effete products or other chemical irritants, or even by mechanical 
irritants, as pointed out by Charles and IJrancis Darwin in connec- 
tion with their researches on insectivorous plants, and the results, 
thougn varying greatly in degree, are absolutely one in kind. Apply 
any irritant to a surface, or a tissue, and the result is a tendency to 
proliferation of the cells. This appears to be the case especially in 
