ACTION OF ALCOHOL UPON CIRCULATION— WOOD AND IIOYT. 



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The objections to the first form of the Williams apparatus as supplied by the Harvard Com- 

 pany, are: First, the great nonintermittent outside pressure upon the heart, K, tig. 2, produced 

 by the liquid in which the heart is immersed and the column of mercury connected with that 

 liquid, in accordance with the ordinary laws of hydrostatics; second, the difficulty of interpreting 

 the graphic records, which has already been spoken of, applies to this as to all other graphic 

 methods of studying the frog's heart; third, at least in the individual form of apparatus supplied 

 by the Harvard Company as we put it up, the pressure on the inside of the heart is excessive. 

 due to the height of the reservoir above the heart. 



The second form of the Williams apparatus seems to us to involve three inherent sources of 

 possible fallacy. First, the heart is working against excessive resistance in raising the column 

 of mercury; second, if by loosening of the clamp or in other method the size of the orifice at 



which the blood escapes becomes in the slightest degree altered, an enormous effect must be 

 produced upon the mercurial column, since the movements of the mercurial column mark simply 

 the relation between the resistance at that point and at the point of pulsation:" third, close, 

 accurate interpretation of the graphic results is for reasons previously explained difficult if not 

 impracticable. 



f In using this apparatus we found that much freer movements took place in the mercurial column when the 

 second valve at D, controlling the backward flow of the blood, was left open; the increased movements of the mercury 

 being evidently due to an increased fall of the column, the result of the reflux of the column of blood into the heart 

 during the diastolic period. It is plain, however, that under these circumstances the interna] pressure upon the 

 ventricles during diastole must equal the weight of the column of mercury, increased according to the laws of 

 hydrostatic pressure, and that in this fact is found a most unnatural condition, the effect of which can not lie 

 estimated. We have experimented with Williams's apparatus both with and without the distal valve: those 

 experiments which yielded the best-looking tracings were without the valve, but we are not at this time able to 

 trace out the differences in the. experimental results. 



