OF CURRENT FORCE DURING SECRETION. 
285 
§ 4. On the manifestation of Current Force during Respiratory Actions. 
Whether the changes which take place in the lungs between the atmosphere and 
the blood, or whether the evolution of carbonic acid be considered as of the same 
nature as a secretion, may be a disputed point. The question, however, as to the 
state of the arterial blood is one of extreme interest, inasmuch as we have hitherto 
found the venous blood to be in a positive state to the secretions, — with the excep- 
tion to the secretion in the stomach in rabbits, as related in former experiments ; and 
the effects here may be reasonably considered as due to the predominant actions 
which occur at the electrode in contact with the mucous membrane of the stomach ; 
— with this exception, we have found the venous blood positive. We have found the 
blood flowing from the portal vein to be positive to the bile, and in reference to the 
liver the portal vein may be considered as its artery ; we can hardly consider the 
blood in the portal vein to form the cation to the bile, but look upon the effects as 
due to the blood being in contact with the cathode. We must bear in mind, that, in 
order to obtain current force, the circuit form must be given to the arrangement^-, 
i. e. that the electrodes must be brought into contact, or by means of some conduct- 
ing mass, with the anion and cation originating the power. The solution of the fol- 
lowing question, viz. JPliat will he the ejfect if we apply one electrode in contact with 
the mucous membrane of the lungs, and the other in contact with the blood f owing from 
it, i. e. arterial blood} is one of some importance. 
Experiment 1. — Rabbit. Pithed. An opening \vms made in the lower part of the 
trachea and the chest laid open. 
One electrode inserted into the right bronchus, the other into the left ventricle ; 
the latter positive 4° or 5°, by making and breaking contact made to increase. 
Between the right bronchus and right ventricle ; the latter slightly positive. 
The former circuit was reformed ; no effect. 
Experiment 2 . — Rabbit. Pithed. In opening the chest the left subclavian vein 
was wounded. One electrode in contact with the right bronchus, the other with the 
blood from the vein ; a very slight effect. 
Between the right bronchus and left ventricle; the latter positive 2° or 3°, by 
making and breaking contact made to increase. 
Experiment 3. — Rabbit. Prussic acid dropped on the eye. Between the left 
bronchus and the right ventricle ; the latter positive 2° or 3°. 
Between the left bronchus and left ventricle, a sudden effect upon the needle 
occurred, but soon became slight ; blood positive. 
Experiment 4. — Rabbit. Prussic acid dropped on the eye. Between the left 
bronchus and the right ventricle ; the latter positive 3° or 4°. 
Between the two ventricles ; a slight effect occurred, sometimes in one direction, 
sometimes in the other. 
Experiment 5. — Rabbit. Prussic acid dropped on the eye. Between the two ven- 
* Faraday, Experimental Researches, vol. ii. p. 51. 
