Dr. Pearson on expectorated Matter. 323 
with a magnifying glass, it appears full of curdy particles. — 
After this agency of caloric, the expectorated matter is much 
less prone to putrefaction. 
2. Distillation of the expectorated matters to dryness af- 
forded a perfectly limpid water, which had a peculiar smell, 
but no impregnation with ammonia ; nor with any other sub- 
stance which could be detected, except a little carbonic acid. 
The residuary matter in a brittle state of dryness, afford- 
ed by evaporation, varied between two and a half and ten 
per cent, of the expectorated substances. The second kind 
yielded one thirty-fifth to one forty-fifth of its weight of 
brittle residue. The first kind afforded one twentieth to 
one twenty-fifth of residue. The third kind afforded very 
different proportions of solid residue, according to its consis- 
tence, viz. one tenth to one eighteenth of its weight. The 
fourth kind gave one twelfth to one fourteenth of brittle 
matter. The fifth kind yielded very different proportions of 
residue, according to the very different proportions of trans- 
parent and opaque matter, of which it consisted — it varied 
between one eighteenth and one thirtieth. 
3. All these exsiccated substances on exposure to -air, grew 
more or less moist, or at least were no longer brittle ; but be- 
came somewhat soft, and, proportionately to the state of mois- 
ture, were augmented in weight. The thinner the expectorated 
matters, the moister and the greater increase of weight they 
generally experienced. But parcels of the same consistence 
from different patients sometimes differed much in degree of 
moisture, on exposure to the air. I have found some parcels of 
the second and fifth sorts of expectorated substances grow quite 
moist, and receive an increase in weight of three per cent. If the 
