6o8 A N A 1 
is contained in the blood may be proved from its heat, 
which, in human blood, and that of fome other animals, 
is from 92 to 100 degrees of Fahrenheit’s thermometer, 
which is more than the mean degree of atmofpherical heat, 
but lefs than the greatefl. Dr. Wrifberg lays, that it dif¬ 
fers in man, according to age, temperament, (fate of mind, 
motion or reft of body, climate, weather, kind of life, meat 
and drink, health, and the various,fpecies and violence of 
difeafe. It is alfo certain that the degree of heat in the 
body increafes a liLtle from an augmentation of heat in the 
atmofphere; but it does not rife to the greateft pitch of 
l'ammer heat. We can live in a much greater heat than 
the heat of the warmed: Cummer, as is proved by perfons 
employed in fugar-houfes, melting-furnaces, by mowers, 
and the ufe of baths and (loves in Finland and RulTia; .and 
alfo by the late experiments of Fordyce, Blagden, Hunt¬ 
er, and Dobfon. The hear of the blood is fometimes Co 
diminifhed in an intenfe cold, that in a perfon froft-bitten, 
but not dead, a thermometer applied to the mouth, arm- 
pits, groins, and even the vagina, would not rife above 
7 6° of Fahrenheit. Is the matter of heat in the blood 
alone ? This is fufficiently probable from phenomena; for 
the heat of the body is diminifhed by haemorrhage, or 
when the blood is intercepted by ligature and compreflion 
from reaching the joints, and is reltored when the blood 
returns. Again, a kind of volatile vapour or exhalation 
continually Hies off from the warm blood, which has a 
fort of foetid fmell, intermediate between that of the fweat 
and urine. After this vapour lias diftipated, the blood 
of a healthy perfon fpontaneoufly congeals into a fcidile 
trembling mafs, efpecially in a heat of about 150 degrees, 
and fooner in feverifh perfons than in Inch as are in health, 
it fometimes coagulates in the veins of a living perfon, and 
•is found clotted in wounds of the arteries. The principal 
part of this coagulated mafs is the crajfamcrtum or cruor, 
•which has the red colour peculiar to itlelf, and gives it to 
the other parts of the blood. This, if it be not kept flu¬ 
id by the attrition of a vital circulation, or fome limilar 
concuflion, runs into a confufed compact, but (oft, mafs, 
like liver, merely by reft and a moderate degree of cold; 
aS it alio does by the addition of alcohol, by mineral acids, 
or by a heat of 150 degrees. It is, either as a fluid ora 
folid, fpecifically heavier than water by near an eleventh 
■part; and, when freed from its water, it is inflammable. 
I11 a mafs of healthy blood, one half or upwards is red cru¬ 
or; and, in ftrong laborious people, the ferum makes only 
a third part; and is ftill more diminifhed infevers, often to 
a fourth or fifth part of the mafs. 
The white yellowilh watery part of the blood, com¬ 
monly called ferum, which feparates from this coagulum, 
tranfuding, as it were, through its pores, forms a fluid in 
which the coagulum (inks; this again feems, though it 
-really is not fo, a homogeneous liquor; it is, in general, 
one thirty-eighth part heavier than water, and almoft a 
•twelfth part lighter than the red globular mafs of crafla- 
anentum. By a heat of 150 degrees, or by mixture of 
mineral acids or alcohol, and by aconcullive motion, it is 
•coagulable into a much harder ma(s than the red cruor, 
and forms firft an indilfoluble glue, then a flefh-like mem¬ 
brane, and at length (brinks up to a horn-like fubftance or 
friable gum. The pleuritic crufts or (kins, polypufes, and 
artificial membranes, are formed from this part of the 
blood. By putrefaction alone, or the diflolving power of 
the air, in a heat equal to 96 degrees, the whole mafs, but 
-efpecially the ferum, dilfolves or melts into a foetid li¬ 
quor; firft the ferum, and then the cruor more (lowly, 
till at length the whole mafs, both of ferum and cruor, is 
turned into a volatile and foetid exhalation, leaving very 
few fceces behind. 
The exabt mafs or quantity of blood contained in the 
whole body cannot be certainly computed. The weight 
of the mafs of humours, however, is much greater than 
that of the folids; but many of them, as the gluten and 
fat of particular parts, do not flow in the circulation. But, 
if wc may be allowed to form a judgment from thofepro- 
' O M Y. 
fufe haemorrhages that have been fuftained without de- 
ftroying the life of the patient, and from experiments 
made on living animals by drawing out all their blood, 
the mafs of circulating humours will be at lead fifty 
pounds; o! which, about twenty-eight will be true red 
blood, running in the arteries and veins; of which the ar¬ 
teries contain only four parts, and the veins nine. The 
blood does not always contain the fame proportion of the 
principles above-mentioned. For an increafed celerity, 
whether by laborious and ftrong exercifes, a full age, fever, 
or otherwife, augments the craftamentum, therednefs, the 
congealing force, and the cohelion of the particles; and 
the hardnefs and weight of the concreted ferum with the 
alkaline principles are increafed by the fame means. On 
the other hand, the younger and lefs adtive animal, and 
the more watery or vegetable the diet on which it is fed, 
the craftamentum of the blood is proportionably leflenecf, 
and its ferum and mucus increaled. Old age, again, lef- 
fens the craftamentum, and the gelatinous part likewife. 
From tliefe principles, and a due conlideration of the 
folid fibres and veflels, the different temperaments are de¬ 
rived. For a plethoric or J"anguine habit arifes from an abun¬ 
dance of the red globules; a phlegmatic temperature from 
a redundancy of the watery parts of the blood; a choleric 
d'fpolition of the humours feems to arife from a more acrid 
and alkalefcent property of the blood; as appears from 
thole, who live on fle!h and on the human fpecies, being fo 
much fiercer and more pallionate than thole who live°on 
vegetable food. A great firmnefs in the folid parts, join¬ 
ed with an exquifite fenfibility, or nervous irritability, dill 
pofes to a choleric habit; a lefs irritability, with a mode¬ 
rate denfity, to a fanguine habit; and a lefs degree, both 
of denfity and irritability, are to be referred to a phleg¬ 
matic temperament. There is alfo a kind of dull heavy 
temperament, in which there is the greateft ftrength of bo¬ 
dy, joined with no great degree of irritability. In the 
melancholic, again, a weaknefs of the folids is joined with 
the higheft degree of nervous irritation or fenfibility. But 
we mull not deferibe the temperaments too fyftematically ; 
for they are found to be not only four or eight, but almolt 
infinitely varied. 
The red part of the blood feems chiefly of ufe to gene¬ 
rate heat, fince its quantity is always in proportion to the 
heat of the blood. The globular figure of its parts, to¬ 
gether with their denfity, makes it eafily pervade the vef- 
fels; and the quantity of iron it contains, as well as of oil, 
perhaps increafes its power of generating heat. And hence 
it is, that the red part of the blood being too much dimi- 
niftied by profufe bleedings, there follows a ftagnation or 
leffened motion of the humours in the fmaller veflels; 
whence fatnefs and dropfy. By the fame rule alfo a due 
proportion of cruor is nece/Tary within the habit, to ge¬ 
nerate new blood. For, by large haemorrhages, we fee 
the blood lofes its red and denfe nature, and degenerates 
into a pale, ferous, or watery, ftate. Health, therefore, 
cannot fnbfilt without a denfe and red blood ; and, if its 
quantity be too much diminifhed, a ftagnation of juices 
takes place, whence the whole body becomes pale, cold, 
and weak. Nor can life or health fubfift without a fuffici- 
ency of thinner juices intermixed with the red blood ; fince 
the cruor, deprived of its watery part, congeals and ob- 
ftrubts the fmalleft palfages of the veflels, and caufes too 
great a heat. 
“ The theory of the temperaments of the human body 
(fays Dr. Wrifberg), in the fenfe commonly received by 
phyficians, and taught in the fchools, the received divi- 
fion of them into four fpecies, and their repeated produc¬ 
tion from the different nature and mixture of the blood, 
favours too much of the ancient and particularly of the 
Galenical doctrine. 1 think there can be no doubt that 
there are temperaments; and that the manner and rule 
which nature follows in man, and likewife in perfect ani¬ 
mals, may be obferved in the performance of the corpo¬ 
real and mental functions, in either preierving or endan¬ 
gering health, in the exercife of moft of the duties and 
2 affairs 
