YAWNING AND SNEEZING 461 



yawning and stretching, and is not infrequently associated 

 with them. The stimulus to the act of sneezing is usually 

 felt within the nasal cavities, and may be produced by the 

 presence of an irritating particle, or as a reflex stimulus 

 from the optic organs, such as is produced by " looking 

 at the sun," and, as it seems to us, from a distension of 

 the Schneiderian membrane, due to a vis a tergo, exercised 

 by pressure from, superabundant cerebro-spinal fluid, such 

 as occurs in the course of a " cold in the head." 



However caused, the act of sneezing consists in filling 

 the chest for a supreme effort to clear the nasal cavities of 

 the offending influence. The act in itself is often experi- 

 enced as a great relief, sometimes, however, it is attended 

 with rather painful feelings, and may assume a pathological 

 character. In the sneezing ushering in a cold in the head, 

 it sometimes at once unlocks the cerebro-spinal spaces, 

 relieving them of their pent-up contents, in the shape often 

 of copious streams of clear, somewhat saline fluid. This 

 occurrence being so frequently attended by appreciable 

 lightening of the sense of weight in the frontal region, and, 

 it may be, by disappearance of the pain experienced in 

 such ailments as gravedo, coryza, etc., may thus be regarded 

 as a natural curative agent. 



In the light of the preceding remarks we would conclude 

 that the nostrils are two of the natural outlets or channels 

 by which the overplus of cerebro-spinal fluid is run off 



Sneezing, etc.," which I read to a company of professional gentle- 

 men in the beginning of the year 1895, and which, along with much 

 more matter of a kindred character, is now awaiting publication in serial 

 -or book form. Sneezing is one of the same class of acts as yawning and 

 stretching, and is not infrequently associated with them. The stimulus 

 to the act of sneezing is usually felt within the nasal cavities, and may 

 be produced by the presence of an irritating particle, or as a reflex 

 stimulus from the optic organs, such as is produced by " looking at the 

 sun," and, as it seems to us, from a distension of the Schneiderian 

 membrane due to a vis a tergo exercised by pressure from superabundant 

 cerebro-spinal fluid, such as occurs in the course of " a cold in the 

 head," etc. 



Dr. St. Clair Thomson's work appeared in due time, and proved to 

 be a most exhaustive description and recapitulation of every published 

 case of what constitutes a pathological demonstration of the physiological con- 

 dition, to which the above quotation is related, and which is elsewhere 

 in this work with much more detail described, along with its factors and 

 the associated cerebro-spinal outlets and excretory phenomena. 



