INH.] 162 
MEDICAL USE OF INHALATIONS. 
These remedies are in many instances true ex- — 
pectorants, acting as mechanical irritants, by — 
immediate contact with the lining tissue of the 
lungs and passages unaccustomed to their pe- 
culiar action. Hence coughing, which is essential — 
_ to expectoration, is excited, and brings up the in- — 
. eer secretion which follows the application of © 
a local’ stimulant to the tissue it pertains to— 
and by this increased local excitement, a more 
vigorous effort is induced in the parts naturally 
concerned in the act of expectoration, by which 
the tenacious mucus already secreted and engorg- 
ing the lungs, is thrown off. 
The steam of hot water is efficacious in reliev- 
ing the distress of paroxysms of asthma, and in 
inflamed tonsils and trachea ; several other inhala- 
tion of class Ist. are also serviceable in the same 
affections. ‘Tar vapours are useful in catarrh an 
phthisis, and more especially in chroniv bronchiti! 
They cannot be employed however in acute inflam- 
matory affections of the lungs, without injury. 
The inhalation of tar fumes has also been benefi- | 
etal in hooping cough, according to the experience 
of Mr Wansbrough, of Fulham in England, and — 
also in his hands, other affections attended with — 
difficult respiration. Womiting as well as cough- 
ing was induced in some children by them. Dr. — 
Crichton, of Russia, published in 1813 an account 
of some experiments made with the vapour of 
boiling tar in the cure of pulmonary consumption. 
Several patients were cured by those inhalations. 
He restricts their use to that stage in which cough 
and hectic are most exasperated, observing that 
if they are persisted in after these are subdued, 
that practice would produce a teasing dry cough 
