1. The theory of the production of gall-bladder lesions in typhoid, by descending infection of the bile from the liver receives support from investigations with the common duct fistula method in the rabbit.
More bacilli appear in the bile with increased doses and more gall-bladder infections are obtained by increased doses.
More bacilli appear in the bile after mesenteric vein injection than after ear vein injection and more lesions result under the first condition.
More bacilli appear in the bile after injection of the same dose in immunized animals than in normal animals and more lesions also result in immunized animals.
In cholera and dysentery the same mechanism is suggested with the additional factor of a portal system septicemia.
2. After the appearance of microorganisms in rabbit bile, their fate is apparently largely determined by the antiseptic properties of the bile.
100 per cent infections cannot be secured by intravenous doses large enough to insure the presence of microorganisms in the bile.
Rabbit bile in vitro may be antiseptic to the microorganisms considered.
The antiseptic action is largely due to its alkalinity. It is apparently possible to protect the rabbit to some degree against gall-bladder infection by a previous injection of sodium bicarbonate.
3. Alkaline therapy is suggested in the prevention and cure of gall-bladder carriers.