Chap. VI.] NOSE AND NASAL CAVITIES. 79 



tumour pressing upon the great veins, in the paroxysms 

 of whooping cough, and the like. The beneficial 

 effect of raising the arms in epistaxis is supposed to 

 depend upon the extra expansion of the thorax thus 

 produced, and the aspiratory effect thus brought to 

 bear upon the cervical veins. The bleeding may be 

 copious and long continued. Thus Spencer Watson 

 reports a case where the epistaxis continued on and off 

 for twenty months without obvious cause. Martineau 

 mentions an instance in which 12 Ibs. of blood were 

 lost in sixty hours, and Fraenkel records a case where 

 75 Ibs. of blood are said to have escaped from first to 

 last. In several instances the haemorrhage has proved 

 fatal. The seat of the bleeding is often not easy to 

 detect, even when the examination is post mortem. 



The nerve supply of these parts is derived from 

 the olfactory nerve, and from the first and second 

 divisions of the fifth nerve. The lachrymation that 

 often follows the introduction of irritants into the 

 front of the nares, may be explained by the fact that 

 that part of the cavity is supplied freely by the nasal 

 nerve, a branch of the ophthalmic trunk. As an ex- 

 ample of transference of nerve force in the opposite 

 direction, may be noted cases where. a strong sunlight 

 falling upon the eyes has produced an attack of sneezing. 

 The olfactory nerves are situated high up in the cavity, 

 and thus, in smelling intently, the individual sniffs 

 deeply and dilates the nostril. The inability to dilate 

 the nostril in facial paralysis, may explain the partial 

 loss of smell sometimes noted in such cases. It is said 

 (Althaus) that anosmosia, or loss of the sense of smell, 

 when following upon an injury to the head, may 

 be due to a rupture of the olfactory nerve-fibres, as 

 they pass through the cribriform foramina. Surgery 

 affords some examples of the possible violence of the 

 act of sneezing. Thus a man sneezed vigorously when 

 his hand was firmly supported upon an object, and 



