Page:Popular Science Monthly Volume 40.djvu/840

818 that some of these forms are highly poisonous. We see this hy what happens to a man when he is drowned. A drowned man is in reality a poisoned man. The waste which is going on everywhere and at every moment in his tissues is producing a poison of so deadly a character that when it can not be oxidized by receiving oxygen from the blood (as it does under ordinary circumstances by means of the two gallons (nearly) of air he breathes in a minute) death ensues in a few minutes. In this case the poison produced all over the system has been no longer rendered harmless by oxygen, and goes as poison to the brain. Now, this poisoning does not appear to be primarily or necessarily due to an excess of carbonic acid, which also accumulates in the blood when a man is drowned. As Dr. Foster shows, even where carbonic acid is got rid of and no oxygen available the same result follows. Thus we have a pretty clear indication that the poisoning which results is the non-oxidization of certain active poisons. Other indications point to the same conclusion. When a man faints from loss of blood he probably faints because the diminished stream of blood does not carry a sufficient quantity of oxygen with it to neutralize the poisons which reach the brain. It is also noticeable that in both these cases convulsions occur—that is, oxygen being denied, the poisons (which retain all their virulence, from being non-oxidized) act as a very powerful stimulant on a part of the nervous center, which, in turn acting through the nerves, throws one set of muscles after another (connected with the respiratory system) into action, in order to obtain the oxygen that is absent; ending at last in that general violent movement which is called convulsions. After a short time the poisons overpower the nerve-centers and death ensues.

Both fevers and violent exercise seem also to illustrate the same thing. In fever the tissue rapidly wastes, and great quantities of waste poison are poured into the blood. These poisons affect the nerves, and are the cause of quickened respiration, and often of quickened circulation, which are necessary in order to