It is worthy of notice, before passing from this part of our subject, that according to Dr. Bell's _views_, the blood is forcibly sent into the great central veins, and there stopped in its course without any attempt to account satisfactorily for its singular arrest, at that point--Dr. Johnson comes to his relief, lifts the veil, and explains why it is kept there and cannot get any further. If the road, he tells us, had been clear and uninterrupted through the lungs, the blood would easily have got round to the left ventricle, and have again gone its round, but it is stopped by the spasmodic contraction of the minute branches of the pulmonary artery, which will not even allow the blood to enter the pulmonary capillaries, as shown by the remarkable anæmia of the texture of the lungs. In this connection may be introduced an opinion as to the cause of the disease and some of its phenomena, which has obtained at least some celebrity, and attracted the attention, if not the careful consideration of the profession. It will account, in part, if founded in fact, for the physiological condition under consideration. It is said, some have observed a chemical change in the constitution of the atmosphere, and have attributed the cause of the cholera to the loss or diminution of its ozone--a principle which is understood to represent what is very properly termed electrified oxygen. Ozone is, therefore, the vital element of the air. It is said that oxygen cannot be assimilated or combined with the blood except when it is in an electrified state constituting the peculiar property or state of ozone. In this state it produces vital electricity of the blood, _which is the life_. The brain is considered and represented as the reservoir of this vital electricity, and the nerves are the telegraphic wires or conductors of it. As a necessary consequence, all acts of material and intellectual life depend upon this double cause. The absence, then, it is affirmed, of this principle, termed ozone--or electrified oxygen--from the atmospheric air in certain localities and the consequent non-aeration or non-oxydation of the blood, may be considered as an efficient cause which will account for some of the most striking phenomena of the cholera. Whether this electrified oxygen, or ozone, is identical with free caloric, it is unnecessary for our purpose at present to determine. It will be admitted that oxygen is the source of animal heat, and when introduced into the system generates its free caloric, which is an essential life-sustaining principle.