Medicine. 253 



Boerhaave's Institutes^ which is his theoretical 

 work, contain all the discoveries in anatomy and 

 physiology known at that time; and that system 

 likewise of pathology and therapeutics which he 

 thought proper to adopt. His Aphorisms, ox prac- 

 tical work, with all their imperfections, contain 

 perhaps more medical learning than any book ex- 

 tant of the same size. 



The most prominent feature in the Boerhaavian 

 system is the attempt to explain the phenomena 

 of the animal economy, whether in health or 

 disease, upon mechanical principles. Under the 

 impression of such opinions he considered the 

 body chiefly as an hydraulic machine, com- 

 posed of a conic, elastic, inflected canal, di- 

 vided into similar less canals, all proceeding 

 from the same trunk, which being at last col- 

 lected into a retiform contexture, mutually open 

 into each other, and send off' two orders of vessels, 

 lymphatics and veins, the former terminating in 

 different cavities, the latter in the heart; that 

 these tubes are destined for the conveyance of the 

 animal fluids, in the circulation of which he sup- 

 posed life to consist, and on the free and undis- 

 turbed motion of which he judged health to de- 

 pend. He therefore believed obstruction to be the 

 proximate cause of most diseases; and this ob- 

 struction he supposed to be produced either by a 

 constriction of the vessels, or by a lentor in the 

 blood. 



In Boerhaave's doctrine of obstruction, which 

 is fundamental in his system, he makes an impor- 

 tant use of Leuweniioeck's supposed discoveries 

 concerning the blood. That eminent microsco- 

 pical investigator had imagined that he found each 

 globule of red blood composed of six serous glo- 

 bules, the serous of six lymphatic globules, the 

 lymphatic of six other globules still finer, and so 



