— 10 —

by probative reasons, the one of the free existence of the acid should be accepted, which in fact better fits with the explanation of the facts.

It still lacks to decide a question, and of great moment, for the perfect knowledge of the sanguinification, and is if the pure and simple dissolution of the oxygen, accompanied of the descarbonization of this, is made or not. The second supposition, that is, the negative, is that to be accepted regarding to important experiences on the blood done by Dumas and by him published, just a while ago, in an instructive memory.

Of these experiences it is deduced that the dissolution of the oxygen in the blood is the first, but not the most important part of the hematosis, that is completed only by the intimate combination of that gas with the solid principles of the blood, certain by chemical affinities.

In the experience, that is long, practiced in order to obtain unaffected and pure the sanguineous globules, he saw that the soda sulphate could not dissolve them, while they conserved the arterial state, during which they behave as if they were truly alive beings.

It was them necessary to conserve them this state, and it got it, submitting them to the continuous influences of the air: equally he saw that the globules of the veined blood took under the influence of the air the arterial properties, being made red rutilant; and that in this phenomenon nor the albumin nor the fibrin is indispensable, because that being gradualy substituted in the blood, already private of the fibrin, the serum for a dissolution of the sodic sulphate, the globules don't become less red. In view of this can be affirmed, except with the whole safety, at least with a lot of probability, that the true end of the breathing is, as says Dumas, to supply oxygen to the sanguineous globules, and to expel the products in that they change; and that the coloring matter of the blood is above all own to take the characteristic color of the arterial, when it joins to the globules of which it is part, property that modifies or gets lost in the destruction or alteration of the globules. This red coloring matter is by Muller called hematin, and it is contained inside the sanguineous cells, formed by the parietal membrane, inside of the which cells it is perhaps united to the globulin, that is also supposed to do part of the parietal. It is exactly of the combination of the oxygen with this hematin that comes the rutilant color that the blood takes, when it is arterialized; resulting the emergence of carbonic acid equally. These facts were investigated by Muller in his experiences on the said hematin obtained perfectly pure.

It is still worth to investigate, before being closed this work, the seat of the formation of the carbonic acid. Of the study of the several theories of the hematosis it is inferred that it doesn't surely come of an unique source. In effect, can give it origin the decomposition of organic matters of the blood in the lungs, the one of the alkaline