In determining the toxicity or organotropism of new compounds in the course of chemotherapeutic investigations, the general custom is to administer solutions to experimental animals and arrive at conclusions on the basis of dosage in relation to the duration of life. While the results are of much value, it would appear advisable to study the less toxic and promising compounds for the kind and degree of tissue injury which they may produce in experimental animals as an additional criterion of suitableness for the treatment of disease among persons and as a guide in the preparation of new chemical compounds not only of least toxicity, but which are also least likely to produce tissue injury.
The purpose of our investigations was to study the histopathologic changes produced in rats and rabbits by the intravenous injection of single large and multiple small doses of arsphenamin and neo-arsphenamin1 as bearing on the