THE HARVEIAN ORATION. 747 



pages, as fully justifies my prediction as it will fully repay any one 

 who will take the pleasant trouble of reading it. The most im- 

 portant result in a practical point of view is the demonstration 

 which Dr. Rutherford has given of the nerve-circle, whereby, in the 

 way of reflex action, the all-important secretion of gastric juice is 

 called forth. The sensory impulse caused by the ingestion of food 

 into the stomach is propagated upwards by the vagi to the medulla 

 oblongata, where it throws into abeyance the vaso-motor nerve- 

 cells, which, whilst the stomach is empty, keep the blood-vessels of 

 the gastric mucous membrane constricted, but which, when their 

 activity is inhibited, allow the zonular fibre-cells of these blood- 

 vessels to dilate, and allow the increased Mux of blood thus called 

 for. That relief will result to some of the countless martyrs to 

 dyspepsia out of the demonstration of this physiological relation of 

 vagus, sympathetic, and peptic glands, I do not doubt. Possibly, 

 I would add, Owsjannikow's observations as to the working of 

 hydrate of chloral as a depressor of arterial tension (Ludwig's 

 *Arbeiten,^ 1872, p. 32) may prove Valuable to persons engaged in 

 practice, by pointing out, in however shadowy a fashion, the road 

 to a more rational and systematised, even if less general use of this 

 drug than that which I am told is now made of it. It may seem a 

 paradox, but it is none the less true for all that, to say that, for the 

 activity of many organs, a paralysing and inactivity of certain 

 nerve-centres in connexion with them is a prerequisite. The ac- 

 tivity of such, indeed of most, organs is but intermittent and 

 occasional, being but intermittently and occasionally called for, 

 whilst the constringing activity of the sympathetic has to be 

 constantly at work to prevent waste of force \ 



Owsjannikow's paper (also to be found in Ludwig's ' Arbeiten,' 6th 

 year, 1871, and in the 'Bericht Math.-Phys.-Klass. K. S. Gesellsch. 

 Wissensch.,' Leipzig) just referred to, and published two years sub- 

 sequently to Dr. Rutherford's, gives, as the result of a number of 

 experiments performed in Professor Ludwig's laboratory at Leipzig 

 on rabbits, and independently at St. Petersburg on cats, the con- 



1 The phenomenon of the distension of the corpora cavernosa, a phenomenon used 

 by Harvey himself in the way of illustration (p. 129 of the 'Epistola Secunda ad 

 Biolanum '), I may adduce in the way of illustration also, being, as it is, dependent 

 upon a similar nervous mechanism ; and being shown so unmistakeably, in cases 

 where it follows lesions in the nuchal region, to result from paralysis of nerve-centres 

 situated there or thereabouts. 



