46 Society for Experimental Biology and Medicine. 



ploys the method of circular compression of Riva-Rocci, and 

 Hill, with the 12 cm. width of armlet proved necessary by von 

 Recklinghausen. The special construction of the cuff allows of 

 adaptation to arms from 1 5 cm. to 34 cm. in circumference. The 

 original feature of the instrument is the folding U tube manom- 

 eter. This is a jointed U tube manometer (copied from Cook), 

 fastened to the under surface of the box-lid, so arranged that, 

 when closed for carrying, it measures io£x4§x ij ins., and, with 

 armlet and inflator, weighs 2\ lbs. The "manometer is perfectly 

 secure when closed and stands firmly when open. The tube 

 caliber is 3 mm. The sliding scale is empirically graduated for 

 each instrument, to compensate for variations in the glass tubing, 

 and is accurate. All connections are of heavy pressure tubing. 

 For inflation a Politzer bag is used, as by Erlanger, except that 

 one with valve is necessary to fill the large armlet. The gradual 

 release of pressure is provided for by a stopcock, with needle- 

 valve of special construction, the work of Mr. Charles E. Dressier, 

 who is making the sphygmomanometer for sale. 



The method of use, as of the other modern sphygmomanom- 

 eters, is based on the criterion of the return of the pulse after 

 obliteration (Vierordt), for systolic pressure, and is similar to the 

 Riva-Rocci and its modifications. A fair approximation of diastolic 

 pressure may also be obtained in most cases, using the criterion 

 of maximum pulsation (Marey, Mosso). This is especially useful 

 in cases of aortic insufficiency, or marked hypertension. For ex- 

 perimental work upon the systolic and diastolic pressures, it cannot 

 compare with Erlanger's more elaborate and costly instrument, 

 but aims to serve the clinician by providing him with an accurate, 

 yet not bulky or costly instrument, for general use. Stanton's 

 sphygmomanometer, which appeared after this one had been 

 begun, answers the same purposes. The only criticism to be made 

 of it is, that 8 cm. width of armpiece does not afford a guarantee 

 of complete accuracy on large arms. 



45. " Demonstration of cytological preparations " : NAOHIDE 

 YATSU. 



The author exhibited seven preparations demonstrating im- 

 portant cytological structures found both in eggs normally fertil- 

 ized, and in some treated chemically. He spoke on the achro- 



