SECT. IV.] OPPOSITE PROPERTY IN THE NERVES. 417 



to the bulbs of the hairs ceases, the small prominences subside 

 and disappear, and in their place there are little depressions, in 

 consequence of which the hairs cease to be erect. 



Other phenomena, occurring in the natural state, besides those 

 mentioned in the preceding paragraphs are intelligible by this 

 congestion arising in the irritated part. And in diseases there 

 are frequently opportunities for observing the operation of that 

 nervous influence on the vessels, in virtue of which fluids flow 

 more copiously and immediately to the irritated part. Inflamma- 

 tion itself is nothing else than a powerful attraction and deriva- 

 tion of blood from a stimulus, by which the vessels become filled, 

 swell, are rendered tense, red, painful, &c.j for eminent writers^ 

 have already demonstrated the incorrectness of the doctrine of 

 Boerhaave, that obstruction is the only cause of inflammation, 

 and all recognise the cause to be a stimulus which attracts the 

 fluids more powerfully to the stimulated part, and produces 

 inflammation. If this stimulus be suflSciently powerful, it 

 draws the nerves of the heart into sympathetic action, and by 

 increasing the movements of the latter produces fever, the con- 

 comitant of inflammation. Eminent men have already taught, 

 that the motion of the blood cannot be so much accelerated 

 through free vessels by the obstruction alone of other vessels, as 

 to excite fever. Thus also haemorrhoids continually arise from 

 the stimulus of hard and acrid faeces in the rectum and other 

 similar causes, since the vessels gradually give way, and dilate 

 into varices, from the frequent derivation of blood to that part. 

 And those deposits, termed metastases by physicians, are pro- 

 bably owing in a great degree to a stimulation of the nerves. 



SECTION IV. DOES AN OPPOSITE PROPERTY EXIST IN THE 



NERVES, SO THAT THEY CAN REPEL THE BLOOD FROM THE VES- 

 SELS UNDER THEIR INFLUENCE INTO OTHER PARTS? 



The face of a man struck with sudden terror is pale, and 

 some men become pale when in a paroxysm of rage, which pale- 

 ness is without doubt owing to a repulsion of the blood from 

 the cutaneous blood-vessels, to those in the interior of the body. 

 Inasmuch as the nervous system is afiPected in terror or rage, 



' Galen, Senac, Gorter, Haller, in Winterl's * Inflamraationis Theoria Nova, 

 (Viennae, 1767) ; and Caldani in his ' Institutiones Pathologiae,' cap. ix. 



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