ON EXPECTORATED MATTER. OQ3 



ferent kinds, from severe fits of coughing in that constant 

 epidemy of the British islands, the winter chronical pneu- 

 monia. 



Different parts of the bronchial membrane being in dif- 

 ferent states m-Aj account for the secretion of the two diffe- 

 rent matters. This seenns more probable, than that these 

 different matters should be secreted from the same part; 

 although it is true, that the same part does secrete at one 

 period transparent thin slime, and at another an opaque 

 thick matter. The former is occasioned by great irritation 

 of the membrane, and the latter is the effect of a more gra- 

 dual secretion with much less irritation. 



For the sake of brevity I avoid a farther description. The 

 practical application of these observations, however impor- 

 tant, would or be suitable in this place. 



The sixth and seventh kinds of expectorated substances 

 being secreted after a quite different manner, and being 

 very different in their nature from the preceding five kinds, 

 I shall not give an account of them in this paper. 



Sect. II. Agency chiejiy of Caloric. 



1. No effect of importance is produced by this agent. Chemical ana- 



until the temperature ofihe expectorated matters is raised 'j^^^; „ ^ 

 o ^ T-. 1 1 • , 1 Actioaofheat, 



to about 1 5* of r ahrenheit s thermometer : then the state 



of aggregation is evidently altered, the viscidity of each of 

 them being diminished. At about 155°, coagulation begins 

 to be quite evident in the lirst, third, fourth, and fifth 

 kinds of matter — that is, curdy masses of various magni- 

 tudes appear in a milklike or whitish liquid. On elevating 

 the temperature to l6o° or 170°, a large proportion of curd 

 is formed ; but the proportion of the curdy matter to the 

 liquid is very different in different specimens. The viscid 

 texture, or tenacity of the expectorated matters, is by this 

 treatment destroyed. The milky liquid decanted, after 

 standing ten or twelve hours, affords, on evaporation to 

 dryness, about three or four grains of residue from each 

 100 grains. 



This liquid passes very slowly through the paper filter. 

 The filtrated liquor affords scarcely more than one per cent 

 ©n evaporation to dryness. By repeatedly boiling in suc- 

 cessive 



