1%, 
equilibrium, a state which appéars to re- 
semble, in many respects, the affections 
observed in typhus: but when the capil- 
lary vessels are contracted, the arteries 
are again distended, althoush without the 
_excess of heat hen must attend their 
distension, from an increased action of 
the heart, and possibly without fever: an 
instance of this aHEe sis: to be exhibited. 
in the shrinking of the skin which is fre. 
queatiy observable from the etfect of 
cold, and in the first impression produced 
by acold bath; such a contraction may 
exist in the cold fit of ‘an intermittent, 
although it seems more probable that a 
debility of the heart is the priniary. cause 
of this affection. 
Having mentioned the general 
of derangement, which appearto be more 
or jess concerned in different kinds of fe- 
ver, the dostor adverts to other and more 
partial ones, which seem to lave a simi- 
tar relation tolocal inflammation: of these 
we shall referto.one only. ‘it is difficult,” 
says. Dr. Young, “to determine, Siecher . 
blushing is more probably effected by a. 
constriction, or by a-relaxation of the 
vessels éanceraed it must, however, be 
chiefly an affection of the ‘smaller Wekcels. 
since the larger ones dy not contain a suf- 
ficient quantity of blood, to produce so 
sudden an effect. Perhaps the capillary 
vessels are aneed, while the arteries, 
which are a little larger only, are con- 
tracted : ndeibie too, atrobstruction may 
exist at the point of junction of the arte- 
ries with the veins; and where the blush is 
preceded by paleness, such an obstr uction , 
is probably the principal cause. of the 
whole affection.” 
As_a practical result from these spe- 
culations, the author expects the theory,. 
which he has explained, may be of use 
i -evabling us to understand the opera-. 
tion of the remedies: employed for rex 
lieving them. . Thus it may be shewn,: 
that any diminution of the tension of the 
arterial system nmst be propagated from. 
the point at_which it begins, as from a 
centre, nearly i in the same manner, and, 
with the same velocity,. as an increase of 
tension, or a pulsation efany kind would. 
be propagated. Hence the etlect of ve- 
nesection must be not only more rapialy, 
but more powerfully feltina neighbour- 
ing, than in a distant part. But since it 
seems probable, that the minute arteries 
are more affected by distension, than. the © 
veins, 
in iflaminatious, from opening anartery, 
rata veiu.: this operation can, however, 
‘Proceedings of Learned Societies. 
causes — 
there 1s reason,.in ¢ general, tU €X-— 
pect a more speedy and eflicacious relief - 
[Ang. 1 o 
be seldom performed without Sistitiad 
inconvenience; for a similar reason, 
‘greater benefit is. often experienced from 
withdrawing a small portion of blood, by 
ineans of cupping or leeches, thana much 
larger quantity.by veneseetion, since both 
athe: former modes of bleeding tend to re- 
lieve the arteries, as immediately as the 
veins, from that distension, which. ap- 
pears. to constitute the most essential 
characteristic of inflammation, . 
‘Mr. Davy read some remarks on Dre 
Ticnry’s expermments, which tended to- ” 
prove that the composition of ammonia 
cannot be ascertained till the nature of. 
nitrogen is determined. Dr, H. thought 
the proportion of hydrogen in ammonia, 
as determined by Mr. Davy, rather low, _ 
-and estimated it at 72 hydrogen and-23 
nitrogen, instead of 74 hydrogep. and 26 
nitrogen ; but Mr. D. having repeated his 
experiments, found them very nearly cor- 
rect, and took 73—27 as the truth. 
A a a Dr. Pearson, on expecto- : 
oe iS, 
ent ae of creche ee differ ay 
rather in the proportion of the ingredients 
than in kind. They all consist of albu=’ 
minous matter, water, and the two prin-- 
cipal ingredients are muriate of soda and 
potash, neutralized by animal oxide, ifnot 
by a destructible acid, besides a small 
proportion of phosphate of limie, annno- 
nia, carbonate of lime, and probably — 
phosphate of magnesia and’ siliceous” 
_earth. -The doctor afnounces that” ot= 
ash neutralized by animal matter is con- 
tained in the blood, and.in most or all of. 
the secreted and excreted fluids, namely, 
in dropsical water, pus, both that se- 
creted without breach of. surface as:well - 
as that of abscesses, and inthe urine, &cy ° 
He has not found the soda, as repre-" 
sented by former chemists, to ampreg~ 
— 
_ nate the animal fluids; and this he'seems 
‘to think might have. been concluded re 
‘priori, because. it is admitted on all — 
hands, that almost every kind of vege-— 
table food: contains the potash united to. 
some matter destructible by fire, which: 
is not the case-of soda; and that it is as 
‘hettle likely the potash ‘should: be altered: 2 
by digestion, as.the muriate of soda itself 
80 constantly taken with our food. It is 
worthy of remark, that the potash is in’ 
much larger: proportion, in expectorated_ 
than i in’ the serum Of the blood 3 — 
_ baalter, 
so. much so, that expectorated, matter, 
when — exsiccated,.. commonly. shows 
air. 
sions of deliquescence on ex yoru tothe — 
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i i ae 
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