The First Hemodialysis Machine
One of the topics that I should like to present to you concerns what is called "vividiffusion". You see before you an apparatus that brings out certain points in this field of vividiffusion. We have here a system of collodion tubes attached to short glass ends at either end of this apparatus.
Through these tubes substances can be made to diffuse out of the blood stream of a living animal. At this point the apparatus is attached to the artery. The blood flows into the apparatus, up one tube and down another and so through the whole system and enters the body again at this point.
Outside of these tubes in this large apparatus is contained a physiological salt mixture. This is in osmotic equilibrium with the blood - this mixture - and prevents the escape of salts from the body fluids. The red corpuscles of the blood and the large protein molecules remain in the blood stream as it circulates in this apparatus.
And only the diffusible crystalloidal substances and some that are not crystalloids but consist of small molecules escape through the celloidin tubes into the outer fluid. Please note that this apparatus is attached to a living animal. So that we have here a part of his blood circulating outside of the body, circulating in this apparatus in such a manner that it can give off diffusible constituents to the fluid outside of the tubes.
In order to allow the blood to circulate in this way in this apparatus outside of the animal body we must mix something with it that will prevent the blood from coagulating in these tubes. The substance that is mixed with the blood is allowed to enter the apparatus at this point. From this tube this substance in solution meets the blood as it enters the apparatus and prevents it from coagulating.
It is a substance obtained from the upper part of the digestive tract of leeches. The leech, when he sucks blood from an animal or a human being, keeps the blood fluid. After a leech has gorged himself with blood if you cut him open you find that his stomach is filled with fluid blood. So in this apparatus the blood remains entirely fluid and the small amount of leech substance that is mixed with the blood is non-injurious to the animal.
The Artificial Kidney
I came to devise this apparatus from the following viewpoint: I was speculating on the sad condition of persons in the terminal stages of chronic glomerulonephritis. These persons vomit continuously, they have severe headaches, their internal organs are engorged but they are often edematous.
As substances accumulate in the blood because their kidneys can no longer excrete them these persons become seriously ill - constant headaches together with some of the symptoms that I have described - and finally there is mental confusion, loss of consciousness, what we call coma, and they may die in this condition.
Now it occurred to me that as long as the kidneys can no longer eliminate all of these substances from the body which when retained cause this toxic state - I say it occurred to me - that if in some way we could remove these toxic substances from the blood of these patients they might be improved, at least for the time being.