Devices are described by means of which the terminals of thermopiles may be held in stable apposition with the mucous membranes of the nasal cavity and postnasal space and local temperature variations thus followed.
Chilling of the body surface has without exception caused depression of the temperature of the nasal mucosa surface, amounting in some instances to as much as 6°C., and indicating marked reflex vasoconstriction and diminution of blood supply. With rewrapping, partial recovery of blood supply promptly occurs, although recovery has been incomplete within the duration of the experiments in ten of twelve instances.
Application of the wires within the nasal cavity has usually caused pain and discharge of clear mucus, sometimes also lacrimation and sneezing. The rhinorrhea has occurred both on the side directly irritated and on the opposite side, although on the former more abundantly, and has apparently been little if at all affected by the diminished blood supply and shrinkage of the mucous membrane incident to chilling the body surface. Discharge from the nose has been at most a rare occurrence in experiments in which the nasal mucosa was not directly irritated.
The temperature of the nasopharyngeal mucosa surface has also been depressed, typically between 1° and 2°C., with chilling of the body surface. This depression has also been shown to have local reflex vasoconstriction and ischemia as its basis. With rewrapping, prompt return toward normal occurs, but here also recovery of blood supply has in the majority of instances not been complete within the duration of the experiments.
The thresholds of the chilling vasoconstrictor reflex to the mucous membranes of the nasal cavity and postnasal space, tonsil, oropharynx, and palate and the threshold of the reflex to the skin of the trunk have been found to be lower than the threshold of the like reflex to the skin of the forehead. Disrobing 'the warmly wrapped subject in a room a little below ordinary room temperature has been found sufficient to cause marked vasoconstriction in the sites of the former group, but only slight or no vasoconstriction in the forehead.
A number of instances of cold or sore throat occurred among the subjects of the experiments, in several instances correlated with somewhat interesting bacteriologic findings which will be described elsewhere.