VOL. XXVI.] PHILOSOPHICAL TRANSACTIONS. 495 



author calculates the velocity of the blood which comes into the liver, and 

 proves, that wha^- comes by the mesenteric artery into the porta, moves 177 

 times slower in the branches of the porta than in the trunk of the mesenteric 

 artery ; and the blood which comes from the spleen to the iiver, moves 200 

 times slower in the spleen, than in the beginning of the splenic artery ; and 

 from thence he deduces the long-sought for uses of the spleen and porta : so 

 productive is one simple truth of many others. 



There is another contrivance for diminishing the velocity of the blood in the 

 testicles, which the author explains, and shows that the blood must be 150 

 times longer in passing to the testicles the way it does, than if it had gone 

 according to the common course of nature. The author then proceeds to ex- 

 plain the ways of forming other secretions, as the cerumen of the ear, the 

 lymph, and animal spirits. He shows likewise how, from the doctrine of 

 attraction, the operation of medicines, which alter the quantity of secretions, 

 may be explained ; for medicines that increase the quantity of any secretion, 

 operate by uniting to and augmenting the attractive force of the particles, 

 which compose the humours to be secerned ; which may be more effectually 

 done by the particles of one sort of medicine than those of another ; and 

 therefore different humours will require different purgatives to carry them off 

 through the glands of the intestines ; which consideration will re-establish the 

 doctrine of specific purges, which was confirmed to the ancients by experience 

 and observation, but rejected by the moderns through a false philosophy. 



He next proceeds to show, how necessary the doctrine of secretion founded 

 on attraction is, for understanding the nature of diseases ; and he gives an ex- 

 ample in a diabetes. He likewise explains from it some of the symptoms of 

 rheumatism, gout, and stone ; as also the operations of medicines in the 

 human body, especially the attenuaters and thickeners of the blood, but more 

 particularly the power of mercury in the cure of a gonorrhaea or pox ; which 

 are all so easily explained by the attractive power of matter, that no one can 

 doubt of the truth of a principle so simple, which yet, like a master key, opens 

 the works of very different contrivances, and discloses a uniformity in all the 

 operations of nature : so that every one may see and read the same thought 

 and hand, in the contrivance and framing of every part of the universe. 



Having given the method by which the several sorts of fluids are formed in 

 the blood, before they are separated from it, he then explains the way by which 

 these liquors are secerned by the glands ; and he proves, that the orifices of all 

 the glands must be circular, and that they can only differ in magnitude ; and 

 therefore all the particles that arrive at the orifice of any gland, and are of a 

 less diameter than that of the orifice, will enter the gland : so that if there 



