i8o MEMOIRS of the 
the Syjlole of the heart prevents their being framed fo large in 
the left ventricle and arteries, as in the right ventricle and the 
veins ^ the blood being carried thro' the former with much 
greater force than the latter. 
Blacki/h unne, Mr. Co-zi.'per thinks, is commonly obferved 
in many feverilh indilpofitions, where the blood is either par- 
tially obflru6led in its return by the veins of the kidneys, or 
thro' Its great velocity in pafiing the kidneys, when fome part 
of the globules of the blood alfo paffes out at the urinary pores 
in the fides of the blood veffels ^ and thefe globules, being 
broken, exhibit thole blackifh bodies, which appear in the 
fediment of the urine^ in thele cafes, the Serum of the blood 
paffes off wi^^h the urine; for by evaporating fuch urine by 
heat, it will become thick, like the true Serum of the blood. 
Obilru6tions commonly begin in the moft capillary veflels, 
firfl, as Mr. Co'vcper frequently oblerved in viewing the tranf- 
parent fins of divers living fifiies with a microfcope; and the' 
it has been hitherto commonly luppofed, that veins and arteries 
are all equally leflened at their extremities, yet Mr. Coivper is 
of opinion, that the extremities of divers blood-ve{t*els are 
much larger than their fellows ^ hence we may account for the 
partial circulation of the blood, and yet mortifications not 
iieccfTarily tnfue, as in the prefentcafe; for the kidney here 
being vaftly dillended, occalioned by a retardation of the 
refluent blood and Lympha, it is conceivable that the obftruc- 
tions began in the membranes, which compole the ^arietes of 
the trunks of the veins and lympha^du6ts, whence an intu- 
melcencc necefTarily follows, and the cavities of thele veflels 
are leflc-ned; cunfequently the refluent blood or Lympha not 
being duly difcharged, thofe larger veflels arc neceflarily 
diflended between their tumefied fides with comprefled 
cavities, and their extremities at the arteries; thus we may 
apprehend how a part remains tumefied under a partial cir- 
culation, and may (when no bad juices taint the blood and 
lympha} continue (o for fome months, nay years, as in 
the prelent cafe, without any diforder to the patient, but 
on luch motions of the body, as accelerate the motion of 
the blood at the extremities of the veflels, when there is 
a greater quantity of blood than can be difcharged bv the veins 5 
whence a iudden intumefcence arilcs, and pain neceflarily enfues. 
What aftringcnt medicines avail in luch like caies, is difficult to 
conceive, but aperitives might be ferviceable. Lofs of appetite, 
bad di^ellion, (s^c. accompany nephritic cales, on account of the 
com- 
