126 SEVENTH REPORT—1837. 
the occasional passage of one form of lung affection into another on 
the coexistence of disease in different and distinct parts of the pulmonary 
structure, the expectoration met with in one form of uncomplicated 
lung disease, may be found in any other mixed with that peculiar to 
the part of the pulmonary tissue principally and originally diseased. 
The appearance of globular bodies in sputa, under the microscope, 
cannot be regarded as decidedly characteristic of any one form of ex- 
pectoration, belonging to all and even to healthy saliva, but differing in 
regard to the extent of globularity in certain affections. From the che- 
mical examination of sputa, it is deduced that they differ from each other, 
in the proportion of soluble albumen capable of coagulation by heat 
which they contain, as also in the amount of fixed or non-volatile saline 
matters. That form of expectoration met with in pituitous catarrh does 
not contain any free albumen capable of coagulation by heat, and, for 
equal weight, less saline matter than any other form of sputum; the 
solid matter also amounts to a very little more than that met with in 
ordinary saliva, and sometimes even less, and although, for equal 
weight it contains less solid and saline matter than any other form of 
sputum, yet for equal weight of dried extract, it contains more than 
other forms of expectorated matter. The sputa in chronic bron- 
chitis differ from the last noticed principally in containing a small 
quantity of free albumen, which heat coagulates, in the larger quan- 
tity of solid matter contained in it, being double that found in the 
sputum of pituitous catarrh, in the quantity of saline matter being less 
in proportion to the solid contents, although, for equal weights of the 
two forms of expectoration, the difference is not considerable. In 
acute bronchitis the albuminous matter found in the expectoration pro- 
bably arises from the presence of a muco-purulent secretion poured out 
by the inflamed bronchial membrane. Sputum, precisely like the 
chronic bronchitic variety, occurs also in the different but more espe- 
cially in the early or middle stages of phthisis, with or without an ad- 
mixture of softened tuberculous matter; in no disease, however, is 
free albumen, capable of coagulation by heat, met with in such abun- 
dance as in the latter stages of phthisis: the absence of such consider- 
able albuminous impregnation cannot however be taken as clear evi- 
dence of the non-existence of phthisical disease, for the latter may exist 
and the expectoration still be of precisely the same character as that 
met with in chronic or even acute bronchitis ; when on the other handa 
large quantity of coagulable albumen is present, the existence of phthisis 
may be strongly suspected, a small quantity of the albuminous prin- 
ciple only being common to phthisis as well as simple bronchial affee- 
tions unassociated with tuberculous disease. Genuine pneumonic ex- 
pectoration always contains coagulable albumen, which appears to be 
derived from the blood to which this form of sputum owes its peculiar 
colour. The quantity of solid matter is considerably greater than 
in any of the preceding forms of expectoration, amounting to more 
than double that met with in the chronic bronchitic variety. The ex- 
tremely tenacious character of genuine pneumonic sputum is probably 
depending upon the existence of a very tough form of mucus resulting 
