AORTIC VALVE INCOMPETENCE 59 



cortex and kidney, the absence of blue from the renal medulla, the deep blue 

 of the adrenal medulla, the absence of blue from the adrenal cortex. Note 

 that with exposure to air the blue intensifies in the parts already blue and 

 that other parts not previously blue become so, e. g. renal medulla. 



Cut open a piece of the gut and note that the mucosa is blue, the muscular 

 coat not so. Note that the liver and lung become mottled with blue. 



Expose a portion of the spinal cord ; note that the surface of the cord 

 becomes bluish under exposure, and that the cross-section of the cord, though 

 not blue when first cut across, b.ecomes blue, the grey matter in a few seconds 

 taking a bright blue tint. The urine is slightly greenish. 



X. To estimate the actual pressure values of the membrane manometer's 

 records, Obs. 36 and 37, it is necessary to gauge the manometer. This may 

 now be done as follows : 



Calibration of the membrane manometer. The manometer and its recording Obs. 37 (cont.). 

 parts were left undisturbed in their position on the kymograph, except for Calibration 

 disconnexion from the arterial cannula. Join the side-branches of the T-tube manometer, 

 leading from the kymograph's reservoir bottle to the connecting- tube of the 

 membrane manometer on the one hand and to the connecting-tube of the Hg 

 manometer on the other. Lower the reservoir bottle to the level of the 

 manometers. Open the top branch of the proximal limb of the Hg mano- 

 meter tube and allow the Hg columns to balance at their zero, and then close 

 it again. Move the kymograph recording-paper to a clean part of the surface, 

 and mark the level of the manometer-lever, thus getting zero mark (text- 

 fig. 26). Then raise the reservoir bottle slowly till the Hg manometer shows 

 25 mm. pressure. Mark the membrane manometer's lever record at this 

 pressure 25. Raise the reservoir bottle till the Hg manometer shows 

 successively 50, 75, and 100 mm. pressure, marking the corresponding heights 

 of the membrane manometer's record. Shift the recording surface to a fresh 

 place and reverse the process, lowering the pressures. 



With these marks as standards, note the values of the systolic and 

 diastolic pressures obtained before and after breaking the aortic valves. 



The kind of result you may expect to find is instanced by the following quotation from 

 data yielded by an individual class experiment : Before the breaking of the aortic valve, 

 systolic pressure 55 mm. Hg, diastolic pressure 36 mm. Hg ; after the breaking of the 

 valve, systolic pressure 53 mm. Hg, diastolic pressure 22 mm. Hg. 



XL Remove the heart from the preparation. Dissect it under water, 



and ascertain the valvular lesion you have made. The usual lesion is a large 



tearing away of the attached base of one of the cusps from the wall of the 



Valsalva sinuses. 



I 2 



