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Such facts as these lend some support to the view which I have advanced as to the constitution of albumen, and I mention them here in order again to call the attention of those interested in chemical physiology to the close relationship which exists between these compounds of prussic acid with the various aldehydes, or the cyan-alcohols, and the different substances which can be extracted from albuminous tissues.
Let me now return from this digression.
From the data which I have placed before you, I wish to draw the inference that in the living animal organisms, owing to slight departures from the normal nutrition of parts, arising probably through nervous agency— the trophic nerves—various substances such as extractives or alkaloids, will be produced, which if not eliminated or neutralised, will lead to pathological changes in the system, absolutely and entirely independently of any bacterial action.
As an illustration I would refer to the pyrexia or fever which, even in healthy individuals, may follow over exertion or excessive fatigue, and which is still more readily developed in convalescents or in persons who are not very strong. Sir William Aitkin has directed special attention to this condition "which is constantly seen in all forms of physical overtaxation or over exertion, as in a prolonged march or by excessive drill, especially in young and adolescent soldiers"—and he refers to the investigations made by Professor Angelo Mosso of Turin on the physiology of fatigue as developed in the soldiers of the Italian army and the pathological manifestations which accompany it. "Fatigue carried beyond the moderate stage, at which it is decidedly beneficial, subjects the blood to a decomposing process through the infiltration into it of substances which act as poisons—substances which when
