152 



THE VASCULAK MECHANISM. 



becomes continuous with B instead of A. and the tube H with A instead of B. 

 There is a further arrangement, omitted from the figure for the sake of simplicity, 

 by which when the disc D is turned through one instead of two right angles from 

 either of the above positions, G becomes directly continuous with H, both being 

 complete!} 7 shut off from the bulbs. 



The ends of the tubes Hand G are made to fit exactly into two canulse inserted 

 into the two cut ends of the artery about to be experimented upon, and having a 

 bore as nearly equal as possible to that of the artery. 



The method of experimenting is as follows : The disc /), being placed in the 

 intermediate position, so that a and b are both cut off from a' and b', the bulb A 

 is filled with pure olive oil up to the mark x, and the bulb B, the rest of A, and 

 the junction C, with defibrinated blood ; and C is then clamped. The tubes H 

 and G are also filled with defibrinated blood, and G is inserted into the canula 

 of the central, H into that of the peripheral, end of the artery. On removing 



FIG. 46. 



Ludwig's Stromuhr and a Diagrammatic Representation of the Same. 



the clamps from the artery the blood flows through G to H, and so back into the 

 artery. The observation now begins by turning the disc D into the position 

 shown in the figure , the blood then flows into A, driving the oil there contained 

 out before it into the bulb B, in the direction of the arrow, the defibrinated blood 

 previously present in B passing by H into the artery, and so into the system. At 

 the moment that the blood is seen to rise to the mark x, the disc D is with all 

 possible rapidity turned through two right angles ; and thus the bulb J5, now 

 largely filled with oil, placed in communication with G. The blood-stream now 

 drives the oil back into A, and the new blood in A through H into the artery. 

 As soon as the oil has wholly returned to its original position, the disc is again 

 turned round, and A once more placed in communication with , and the oil once 

 more driven from A to B. And this is repeated several times, indeed generally 

 until the clotting of the blood or the admixture of the oil with the blood puts an 

 end to the experiment. Thus the flow of blood is used to fill alternately with 

 blood or oil the space of the bulb A, whose cavity as far as the mark x has been 

 exactly measured ; hence if the number of times in any given time the disc D 

 has to be turned round be known, the number of times A has been filled is also 

 known, and thus the quantity of blood which has passed in that time through 

 the canula connected with the tube G is directly measured. For instance, sup- 



