The auto-toxins of intestinal origin comprise by far the greater number of factors which may act as causes and by far the most virulent of the intrinsic poisons. Endeavoring always to exclude poisons which enter the body as such, and which, therefore, do not properly contribute to autogenous disease, we find that the chief substances to be considered are the bile, certain ptomaines and leucomaines, acids formed by intestinal changes and poisonous gases.

The Bile

The Bile may not properly be termed an excretion as its constituents are largely resorbed from the intestine, and for this reason there is no equilibrium between the sulphur and nitrogen constituents of the bile and the amount of proteid decomposed in the body.

That the bile is toxic is readily demonstrated, for four to 6 cc. per K. causes death in convulsions. Of the biliary constituents the coloring matters are the chief poisons, for the bile loses two-thirds of its toxicity when decolorized.

Bilirubin

Bilirubin is the chief pigment and it is derived from hemoglobin through hematin as shown by the following symbols:

Hematin,

C32H32N4O4Fe

Bilirubin,

C32H6N4O6

Biliverdin,

C32H36N4O8

When hemoglobin is infused into the blood, bile pigment appears in the urine. The bile salts also do this as they liberate hemoglobin by the destruction of the red blood corpuscles.

Uroerythrin

Uroerythrin is the essential pigment of red urines, is unstable, existing only in acid media, and has a characteristic spectrum. Although not a strictly normal constituent of urine it occurs when there are slight variations from health, in diseases of the liver, acute rheumatism, pneumonia and passive congestion of the lungs it is enormously increased. Hematoporphyrin also has a characteristic spectrum, but as yet there is but little positive knowledge as to its precise origin or the proportion in which it exists in the urine. If excreted in excess it indicates increased hemolysis and it may also be found in the urine of patients who have taken sulphonal.