Acute coryza may be produced traumatically by the inhalation of irritating gases. Owing to a peculiar susceptibility, which with some persons is an idiosyncracy, the powder of certain substances, especially epicacuanha, produces the affection. This is probably the explanation of the coryza which occurs in cases of so called hay asthma or hay fever. The affection is an element in certain infectious diseases, especially rubeola, or measles. Iodine, taken internally, in some persons produces this affection. I do not purpose in this paper to consider the affection as occurring in the etiological and pathological connections just named, but as constituting what is commonly known as a "cold in the head," and the incipient stage of the epidemic disease known as influenza.
When a person is said to "have taken cold," usually, as every one knows, the nostrils are first affected. The affection may go no further; but in most instances