3:20 Medicine. [Chap. IV. 



haave's opinion, the diameters of the vessels also 

 decreased in the same regular series, perfectly cor- 

 responding with the size of the globules. This 

 explains his frequent introduction of error loci in 

 his account of obstruction and inflammation. But 

 as the notions of Leuwenhoeck on this subject are 

 now generally exploded, so likewise must be the 

 inferences and doctrines grounded upon them. 



It was taken for granted by Boerhaave and by 

 almost all preceding medical writers, that diseases 

 always arise either from some depravity of the fluids, 

 or some fault in the composition or cohesion of the 

 simple solids; and that wherever such disorders ex- 

 ist, they are always susceptible of a definite charac- 

 ter, and placed vrithin the reach of the senses. He 

 believed the fluids to be liable to contamination by 

 acid andx alkaline acrimony, and by other morbific 

 inatters variously constituted, and to be disordered 

 by lentor and excessive tenuity. The simple solid, 

 according to his doctrine, is subject to very frequent 

 chano-es of condition, from weakness and exces- 

 sive stiffness or elasticity, and from laxity and 

 rigidity. 



Boerhaave supposed the proximate cause of fever 

 to consist in a lentor or viscidity prevailing in the 

 mass of blood, and stagnating in the extreme vessels. 

 To this he attributed the cold stage of fevers, and 

 all its consequences. It is true that he afterwards 

 introduced, though with some doubt and hesitation, 

 as an additional part of the proximate cause, an 

 inertia of that portion of the nervous fluid which 

 is destined to the heart. It was one of his positions, 

 that the morbid heat in fever, being a symptom 

 only, might therefore be disregarded. 



