185 
PATH OLOG Y 
to. D, extran'ea, (D. terrea, Cull.) From calculous or 
other earthy fecretions in the fubftance of the lungs 
thrown up by coughing. See Catarrhus, in this article. 
0 . D. phlegmatica, (D. aquofa, Cull.) The habit 
phlegmatic or cachectic, with fcanty fecretion of urine, 
and moltly oedematous extremities. See Hydrops, in this 
article. 
y. D. pinguedinofa, or purfinefs ; accompanied with 
oppreffi.ve fatnefs. See Corpulence, in this article. 
o. D. organica, (D. thoracica, Cull.) From deformity 
or organic defect, or injury. 
e. D. vaporofa j from the mifehievous a&ion of metals 
or other poifons,. 
i. Dyfpncea exacerbanst SuhjeCt to fudden and irre¬ 
gular exacerbations: the breathing deep, ftertorous, 
acute, and Suffocative; relieved by an ereCt polition. 
This, when not Symptomatic, is the fame as the follow¬ 
ing genus, varying from it only in its acutenefs and 
violence; it requires a fimilar treatment. Found, alfo, 
under the one or the other fpecies, as a Tymptom in 
aneurifms, polypous concretions, and other affections 
of the heart and larger veflels; in enlargements and 
other a (left ions of the abdominal vifeera ; in empyema, 
iiydrotborax, worms, peripneumony,baftard peripneumo- 
ny, fmall-pox, and occalionally in fevere attacks of inter¬ 
mitting fevers. 
Some au thors have explained the term Catarrhus fuffo- 
cativus (the name by which this fpecies is called by 
Baglivi and others) as Synonymous with croup. 
Genus III. Afthma, [probably from ctw, I breathe.] 
Difficulty of breathing, temporary, recurrent; accom¬ 
panied with a wheezing found, and fenfe of conftriClion 
in the cheft; with cough and expectoration. Thefe ge¬ 
neric characters are fubjeCt to great variations. Afthma 
lias of late years been traced in a very large proportion 
of cafes to organic changes in the thoracic vifeera. As 
there leeins good reafon, however, to believe, that the 
majority of afthmatic patients (perhaps nearly all where 
the complaint is not of long Handing or of peculiar vio¬ 
lence) Suffer from functional impediment only, we con¬ 
fine ourfelves to the confideration of afthma of this latter 
kind. 
The exaCl nature of afthma is not fettled. Among the 
■old writers, Floyer paid much attention to this difeafe, 
with which he was feverely aftlidted ; but his opinions as 
to its caufe are fo much tainted with the humoral doc¬ 
trines, that it is ufelefs to difeufs them. He has left, 
however, a very good description of the Symptoms of one 
kind of afthma. Cullen fuppofed it to confift in a fpaf- 
modic conftridiion of the mufcular fibres of the bronchia, 
preventing the free ingrefs and egrefs of the air, and con¬ 
sequently the due expanfion of the lungs. This opi¬ 
nion, however, is not reconcileable with the known 
ftrudhire of the bronchia, and lias accordingly been laid 
afide. The fame author mentions feveral varieties of it, 
as exanthematicum,fimplex, phlegmaticum, plethoricum, 
&c. arifing from remote and diftindt caufes. Thefe Dr. 
Good has adopted in his Nofology ; but the Amplified 
arrangements of pradfical writers feem to warrant the 
difmifial of Such divifions. Dr. Bree, in the belt treatife 
on this Subject which we know of, confiders afthma, pro¬ 
perly Speaking, and as diftinguifhed from mechanical 
preffure of all kinds, whether tumors, concretions, or 
other confequences of inflammation, to be a material 
irritant applied to the air-cells of the lungs, and exciting 
the contraction of the refpiratory mufcles for its remo¬ 
val. To take in his juft and more extended view of the 
difeafe, we quote his own words. He fays, “ If it be ne- 
cefiary to define the difeafe, I would fay, agreeably to the 
principles of the following inquiry, Afthma is an excef- 
hve contraction of the mufcles of refpiration, without 
acute lever, excited by an irritation in Some of the vifeera 
whofe functions thele mufcles are intended to ferve. 
Under this generic definition are comprehended all affec¬ 
tions not febrile, attended by an uncommon adtion of 
the mufcles ufed in refpiration ; the influence on thefe 
mufcles being the fame in kind, though diftindt by fitu- 
ation and quantity of force, as it may exill in fome of the 
lower vifeera, or in the lungs.” 
Now, as far as regards the lungs, the material irritant 
productive of afthma is fuppofed to be a mucous fecre¬ 
tion. Dr. Bree deduces, from a valt ftore of ancient and 
modern authors, observations tending to (liow, that the 
paroxyfm of afthma'is ahnoft invariably connedled with, 
and terminated by, the expectoration of mucus or Serum : 
and he infers, that the impediment to refpiration arifes 
from the gradual collection of this fluid in the air-cells. 
There it may exift for a certain time without producing 
dilturbance; but at length the filling up of the remote 
terminations of the bronchite impedes the changes of the 
blood, and calls into forcible adtion the refpiratory 
mufcles; whereas the lymph accumulated in the air-cells 
is rather oppreffive than acrimonious, and the fenfib'.lity 
of their membrane is lefs than that of any part of the 
bronchia and trachea. Moreover the veficle cannot col- 
lapfe in the attempt at expiration, becaufe its cavity 
is filled with lymph. Hence Dr. Bree thinks arifes the 
true caufe of a paroxyfm, “ beginning with little or no 
cough, and that Seemingly impeded but, after the 
fluid has been leflened by abforption, Still more may be 
discharged in the vapour of expiration, and, the elafticity 
of the bronchia being thus reftored, the much-defired 
fpitting of mucus may take place. 
We copy from this author the following lucid account 
of his opinion-sas to the production and -nature of this Se¬ 
cretion. “It is obvious, that mucus could not have been 
expeCtorated without a previous Secretion of ferum. But, 
as this mucus is copioully discharged, the effufion of Se¬ 
rum mutt have been confiderable : it may be therefore 
proper to inquire in what ftate of the lungs fuch an effu¬ 
fion can take place. It is known that the glandules of 
the trachea and bronchia are fubjedt to inflammation, and 
that in catarrh an excretion of mucus is confiderable 
from this condition of their veflels; but practitioners 
have generally teftified, that pyrexia and Symptoms of 
inflammation are not prefent in fpafmodic afthma. We 
muft then look farther for the fource of this copious fe¬ 
cretion, and we (hail find it in the veflels with exhalent 
orifices at the extremities of the air-pipes ; the conftruc- 
tion of which is not complex like that of the mucous 
glandules; and they have not follicles in which they may 
depofit their lymph till it be excreted. There are many 
reafons for believing this to be the principal, if not the 
only, fource of the copious expeCforation in afthma.” 
In confequence of the condition of the habit in afthma, 
the matter of heat is not given out in this as in other in- 
ftances of glandular Secretion. Thecapillary veflels are 
paffive in this difeafe; and, not contraCfing So narrowly 
as to detain the grofs part of the current, they permit 
lymph to pafs inftead of exhaling only a thin vapour. 
It Seems that, in the early periods of afthma, and while 
ferum is not very abundantly effuled, a quicknels of ref¬ 
piration commonly precedes the paroxyfm, and the ex¬ 
pirations carry off, in vapour, that fluid from the cavi¬ 
ties : the aCtion of the abforbents is probably alfo quick¬ 
ened, fo that, by the united powers of thefe inftruments, 
the balance may be reftored between abforption and ex¬ 
halation. 
There can be little difficulty in according to Dr. 
Bree, that this explanation is very plaulible and fatisfac- 
tory, and that irritation of mucus on the nerves of the 
bronchia is no doubt in many cafes the proximate caufe 
of afthma. Every one muft allow, however, that'any cir- 
cumftance inducing an irritable ftate of the nerves will as 
furely produce the difeafe as the fecretion does; and it 
is of little confequence what irritant is applied to thefe 
nerves, Since we find cough and difficulty of breathing 
produced by a variety of ailments, as in the liver, womb, 
kidneys, See. We therefore confider afthma the refult of 
irritation 
