m 
undergoes in the act of coagulation . 
acquires that texture, which fits it, when extravasated in 
living animals, to open a communication with the general 
circulation, and by that means become a part of the solids of 
the animal. 
It has ever been a desideratum to ascertain in what manner 
blood after it had coagulated, and remained at rest in different 
parts of a living animal, is rendered vascular. The fact itself has 
long been known to every enquirer into the operations of the 
animal economy, and several theories have been formed to ex- 
plain it. Mr. Hunter, who perhaps understood the appearances 
such coagula put on, when injected from the neighbouring 
vessels, better than any other physiologist, was unable to 
trace a direct continuation of ramifying branches from the 
circumference of the living parts to the centre of the coagu- 
lum, and therefore referred it to a principle of life existing in 
the blood, which principle was consequently inherent in the 
coagulum, and formed a series of vessels, pervading every 
part of it, which opened for themselves communications with 
the surrounding vessels. Since Mr. Hunter’s time, no more 
satisfactory opinion has been advanced for the explanation of 
this curious phenomenon. I confess that my own attention 
has not, for the last twenty years, been called to this enquiry, 
although before that time, while I was assisting Mr. Hunter 
in the prosecution of his pursuits, I gave considerable atten- 
tion to it, but remained unsatisfied with all the explanations 
that had been given. 
My attention w as, however, again called to this subject last 
summer, by different conversations I had with Mr. Bauer, in 
which he told me, that to illustrate the germination and, vegeta- 
