laterally, does the rectus externus of the eye on that side, act at the same 

 time as the rectus interims of the other eye? The indispensable utility 

 of this phenomenon, in keeping a parallelism of the axis of vision is very 

 obvious, but who can assign the cause? Why are rotatory motions, 

 in different directions, performed with so much difficulty by the arm 

 and leg of the same side of the body. Can it be called a just idea of 

 the innumerable varieties of this phenomenon, and of its frequent ano- 

 malies, to say, with Rega, that there are sympathies of action or of con- 

 tractility (consensus actionum) sympathies of sensibility (consensus passio- 

 num. ) 



All these difficulties render it pardonable in Whytt, to have consider- 

 ed the soul as the sole cause of sympathy? which was, in fact, a modest 

 avowal of the difficulty of explaining the subject. We are not justifi- 

 ed in considering sympathy as an anamolous action, as an aberration 

 of the vital power*. Can it be said, that the natural order of sensibility 

 and irritability is inverted, in the sympathetic erection of the clitoris and 

 of the nipple, or in the turgesence of the breasts, determined by the gra- 

 vid state of the uterus? 



It is by means of sympathy that all the organs concur in the same end, 

 and yield each other mutual assistance. It affords us the means of ex- 

 plaining, how an affection, at first local or limited in its extent, spreads 

 and extends to all the systems ; it is thus that every morbid process is 

 carried on. The diseases termed general, always originate^ through the 

 medium of association, in the insulated affection of an organ or a system 

 of organs. 



In fact,, the affections which appear to us most complex, in the number, 

 the variety, and the dissimilarity of their symptoms, consist of only one, 

 or of a small number of primitive or essential elements, all the rest are 

 accessory, and depend on numerous sympathies ot the affected organ, 

 with the other organs of the animal (Economy. Thus, if the stomach is 

 the seat of irritation, from foulness of its contents, pains of all kinds 

 come on, but especially in the head and limbs, with a burning heat, nau- 

 sea, loss of appetite, anxiety, and these symptoms constitute a disease, 

 which appears to affect the whole system. 



To go on with the same illustration, the stomach, when oppressed by 

 irritating substances, contracts spontaneously to get rid of them. The 

 universal disturbance which their presence occasions, seems directed to- 

 wards the same end, as if the suffering organ called upon all the others to 

 assist in relieving it. 



These synergies, or aggregate motions, tending to one end, and arising 

 out of the laws of sympathy, constitute the diseases termed general, as 



* Sympathy may be considered that state v/hich an organ or texture presents, which 

 hokls a certain relation to the condition which characterises another orgun or texture* 

 in health or in disease : or it may be viewed as a certain relative state of the vital power 

 as it exists in separate organs or textures ; as when one part is excited another par- 

 ticipates in the change and evinces a similar feeling-, motion, or function. 



Sympathies may be classed into the reflex and direct. The former may be chiefly 

 referred to the cerebral nerves and to the reaction of the sensorium, as when the 

 Schneiderian membrane is irritated the diaphragm is affected in consequence of the 

 excitement conveyed to the brain, and thence to this muscle by means of its voluntary 

 nerves/ The latter class takes place independently of the sensorium, and arises from 

 the ramification and distribution of the ganglial nerves, especially those which are sent 

 to the Muscular system. For the elucidation of this subject, sec APPENDIX, Note E. 



