CLASS II. i. 2. 4. OF SENSATION. 1*9 



attends the infpirations in the latter, and there was no attendant 

 fever ; and the difeafe was cured by one venefection, and a 

 moderate dofe of opium after the venefe&ion. See afthma 

 convulfivum. Clafs III. i. I. 10. 



A conwtlfive difficulty of refpiration may thus be eafily dtf- 

 tiriguifhed from the croup ; as in the former the patient draws 

 in the breath eafily, and then voluntarily clofes the larynx, and 

 voluntarily ufes great exertion in forcing out the breath, with 

 defign to relieve f$me pain by this violent exertion, as in parox 

 yfms of eptlepfy. 



On the contrary, in the croup the breath is eafily expired, 

 but the infpirations are attended with the utmoft difficulty. 

 This difficulty of infpiration may be feen by viewing the region 

 of the ftornach i as when the child raifes the fternum for the 

 purpofe of drawing in its breath, the preflure of the atmof- 

 phere on the pit of the ftomach prefles the diaphragm upwards, 

 and makes a fudden and great hollow in the fcrobiculus cordis^ 

 This difficulty of infpiration, and not of expiration, is alfo known 

 by the harfli found , which only attends the infpiration. 



This difficulty of infpiration may in part be owing to this cir- 

 cumftance. In directing thofe children who have died of the 

 croup, I believe the upper part of the adherent coagulable lymph, 

 or indurated mucus, formed within the trachea, is found to be- 

 come loofe, and to feparate from the upper part of the trachea 

 before the lower part of that adhefive membranous cruft begins 

 to feparate, and hence the loofe upper part at the time of infpira- 

 tion is bent downwards into the trachea, and thus becomes dou- 

 ble, and obftrucb the paflage ; but this duplicature of it does 

 not happen in expiration. See Tranfact. of a Society, Vol. II. 

 Account of Croup, by Henry Ram ley, cafe the 8th. Might not 

 this be prevented from being fatal, by an aperture into the wind- 

 pipe beneath the larynx ? 



I have very lately feen a mod diftinct cafe of this peripneu- 

 monia trachealis, or croup. The child, about ten months old, 

 had great difficulty in drawing in its breath, with much noife ; 

 but had much lefs difficulty in its expiration, with little or gener- 

 ally no found. On obferving its naked cheft, the fternum, or 

 breaft-bone, was feen to be raifed with great force -, and then the 

 diaphragm, and the bowels under it, rofe haftily up into the low- 

 er part of the cavity of the cheft ; and the air ruined with diffi- 

 culty, and with great found, through the contracted larynx into 

 the upper part of the cheft ; both thefe effects were evidently 

 owing to the prelTure of the atmofphere, to fupply the vacuity, 

 which muft otherwife fucceed the forcibly railing of the fternum. 

 Why the difficulty of infpiring was fo much greater than 

 VOL. II. Y of 



