Abstract
Chronic anemia was produced in rabbits by the injection of Welch B. toxin. The blood picture was characterized by (1) low color index, (2) anisocytosis without distortion of the shape of the cells, (3) rarity of nucleated red corpuscles. The histological examination of the organs showed changes consistent with blood destruction from any cause. Study of the spinal cord for degenerative changes, such as are frequently found in pernicious anemia, were negative.
The anemia which developed, however, was characterized by remissions when the injections were continued over long periods of time. The blood picture in rabbits which were given non-fatal doses returned to the normal despite the continuance of injection of the toxin. If large doses were then given the resistance could be broken down and anemia once more produced. This phenomenon could be repeated. It seemed, therefore, theoretically possible that the remissions in pernicious anemia were due to a varying immunity on the part of the human organism to the Welch B. toxin, and that, furthermore, the protoplasm of the rabbit was not designed to produce the typical changes of pernicious anemia as it occurred in man. For this reason it seemed important to determine the immunologic reactions associated with anemia due to Welch B. toxin, and compare them to those observed in pernicious anemia.
A study of the anti-hemotoxin furnished a method for making comparison between the clinical and the experimental anemia. As shown by Bull and Pritchett, 1 Welch toxin when mixed with serum containing anti-hemotoxin and injected intravenously into an anima1 does not result in destruction of red cells, whereas the toxin injected alone causes severe anemia and death.
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