Yellow Fever. Possible Use of Rhesus Monkeys by the Germans, To Prepare a Vaccine, or in Connection with Offensive Measures. Note by Secy.

5. An attempt at spreading yellow fever in British India in this way would appear to be fraught with difficulties since either a number of infected monkeys would have to be transported from Germany to India a task of considerable difficulty since the infected monkeys usually die within less than a fortnight of infection or the mosquitos which had been infected by feeding on the monkeys in Germany would themselves have to be transported to India. This latter expedient involves the difficulty that the mosquitos would have to be fed every three or four days and though they could be fed on a suitable small animal such as a guinea pig, it would not be easy for the enemy agent to do this inconspicuously.