INDIAN SNAKE POISONS,
produced, is merely temporary, and after an interval of uncertain duration the respiration will be found to be slower, and the slowness to increase. The respiratory movement is also lessened in extent. The slowing and lessening of the respiration become at last too great to allow of the blood being properly oxygenated, and, after the usual symptoms characteristic of asphyxiation, the animal dies.
The simplest form in which one can observe the effect of cobra-poison on respiration, is afforded by the common fowl. The stethometric chart marked No. I, gives, in a concise manner, the effects of cobra-poisoning when the action is very gradual. The first line gives the normal respiratory tracing. The main points to be noticed in the succeeding tracings, are the slight quickening first perceived, and the increase of the excursus. These are followed by rapidly increasing retardation, with a certain amount of lessening of the excursus, though the excursus is less affected than the frequency. It is also to be noticed that inspiration becomes sudden and abrupt, and is immediately followed by an expiration equally sudden. The movement that remains, therefore, allows no time for that gradual filling and emptying of the air-spaces of the lungs, that would permit a free interchange of air, and is thus necessarily peculiarly unfitted for respiration. In line VI. these characters are well marked, the slowing especially being excessive. A kind of struggle against the poison is to
