A number of unique medical problems might be created when man is exposed to an infectious agent through the respiratory route rather than by the natural portal of entry. Some agents have been shown to be much more toxic or infectious to experimental animals when exposed to aerosols of optimum particle size than by the natural portal. Botulinal toxin, for example, is several thousand-fold more toxic by this route than when given per os. In some instances a different clinical disease picture may result from this route of exposure, making diagnosis difficult. In tularemia produced by aerosol exposure, one would not expect to find the classical ulcer of ``rabbit fever'' on a finger.

An enemy would obviously choose an agent that is believed to be highly infectious. Agents that are known to cause frequent infections among laboratory workers such as those causing Q fever, tularemia, brucellosis, glanders, coccidioidomycosis, etc., belong in this category.

An agent would likely be selected which would possess sufficient viability and virulence stability to meet realistic minimal logistic requirements. It is, obviously, a proper goal of research to improve on this property. In this connection it should be capable of being disseminated without excessive destruction. Moreover, it should not be so fastidious in its growth requirements as to make production on a militarily significant scale improbable.