476 MEM O I R S of the 
that extraordinary veffel, was nothing but the mucilaginous hu- 
mour, which is continually dilcharged by the glands of the 
Trachea ^ and being grown more clammy by the diftemper, was 
reduced to a kind of "jelly by the drynels of the air, whereby not 
being able to Ipit it out, it incruftated the infide of the Trachea 
and "BronchitG^ and growing thicker, was at laft fhaken off by 
the violent fit of coughing the child was fometimes taken with, 
and then it was again renewed by the fucceeding Mucus ; this new 
veflel would not diflblve in hot watery the veflels of the lungs, 
that h^ the Trachea and Sronchia^i the pulmonary arteries and 
veins were all found and entire. 
"The Circulation and Globules of Sloodin Butts 5 by M. Lee- 
wenhoeck. Phil. Tranl! N^ 2^3. p. 552. 
MZee-it'enhoeck having feveral times examined butts, fome of 
which, bating the tail, was but an inch long with a mag* 
nifying-glafii, in order to fee the circulation of the blood, and the 
variety of its motion f he again confidered thole little particles 
which conAitute the blood of a red colour, which he formerly 
aflerted to be flat and oval ^ the greateft motion of the blood 
oblervable thro' the fins, was on each fide of the various little 
fingle bones placed therein, where the blood-veflels werefo large, 
that 2 5 of the abovementioned particles could pais a-breaft, but 
difappeared as they drew nearer to the extremity of the fins, fmall 
veflels being all along detached from the arteries 5 on one fide 
of a little bone runs an artery, and on the other a vein, 
correfponding thereto ; and befides, he obferved a vein and 
an artery lying fo dole together, as if their coats had been 
united 5 from the abovementioned artery there arofc fmaller 
veflels a-crois the membrane between the little bones, and 
after they had run out the breadth of three or four hairs, 
they united again into one vein 5 thefe fmall veflels re- 
ceive about two or three particles of the blood at once, efpe- 
cially if the fi/h lies ftill 5 and confequently its little bones clofe 
to each other, when it exercifes its fins in fwimming, the dif- 
tance between the little bones is enlarged, the interjacent 
membranes llretched out, and the blood-vcflels that run a-crofs 
them, efpecially thofe in the tall-fin, are drawn out fo, as to 
be twice as long as before 5 M. Zeeivenhocck finding it eafy to 
extend the tail-fin, he accordingly flretched it to a breadth 
equal to what the filh gives it in Iwimming, in order to obfervd 
the motion of the blood in the thus extended veflels 5 he 
found, that whereas, when the fifh did not move, the fmall 
veflels 
