30 ON THE LACTEAL AND LYMPHATIC ABSORBENTS. 
while, on reconsidering the subject, I find that although these 
gentlemen in the year 1762, in their medical commentaries, 
stated the absorption from the serous surfaces as one of their 
positions, yet I now find that this idea was taught by Boer- 
haave before the year 1743, and, to prevent any misunder¬ 
standing, I here introduce his own words on the subject. 
‘‘ Hippocrates distinguished the solid parts of the human 
body into cavities and vessels; the cavities in a healthy body, 
he says, are full of vapours, but in a diseased body full of sharp 
humours, or ichor. And it is certain that all the cavities and 
interstices in the human body are supplied with a waim and 
moist vapour, which renders the membranes and muscular fibres 
pliable and fit for motion, and prevents them from adhering to 
each other. But this vapour is never discharged in such quan¬ 
tities as to turn into liquor, and prove offensive ; for, upon open¬ 
ing the thorax or abdomen of a living brute, nothing but a 
vapour exhales without any water remaining; this vapour must 
therefore return again into the blood, which it can do by no 
other vessels that we are yet acquainted with, than the lymphatic 
veins. Dogs have a communicating passage from the testicles 
into the cavity of their abdomen, which is not found in men. 
Nuck, therefore, wounded the scrotum a dog, and injected a 
pound of water thereby into the cavity of the abdomen, sewing 
up the wound after the operation. The dog afterwards voided 
all the water by urine within the space of three days ; so that no 
part thereof was found remaining in the abdomen. There must, 
therefore, be an open and continued passage from the cavity of 
the abdomen to the receptacle of chyle. The warm and subtil 
vapour which is natural to the body, will be, therefore, much 
more easily admitted by the same vessels, though its quantity be 
not inconsiderable; which is argued by the largeness of the cavi¬ 
ties which are moistened therewith, as those of ihQpelvis, scro¬ 
tum, abdomen, thorax, pericardium, cranium, ventricles of the 
brain, cavity of the lungs, stomach, intestines, &c. The same 
is also argued from the sudden increase of a dropsy, where the 
vessels are not affected, but only the absorption of this vapour 
obstructed. As this vapour, therefore, appears to be so copious, 
it must have no small share with the other part of the lymph in 
assimilating the chyle, and rendering it the more easily converti¬ 
ble into blood and other juices proper to the human body*.” 
* Professor Boerliaave’s Academical Lectures on the Theory and Prac¬ 
tice of Physic, vol. i., p. 3G1. 1743. 
