658 



FLOW OF BLOOD THROUGH KIDNEY. [BOOK n. 



the other (Fig. 89), called the oncograph, is the recording part of the 

 apparatus. Any diminution in the volume of the organ (Fig. 88, K), 

 kidney, spleen, &c. as the case may be, diminishes the pressure on the 

 fluid in the chamber a ; some of the fluid in the chamber M (Fig. 89) 

 accordingly passes through the tube ^(Fig. 89) and the tube T (Fig. 88) 

 to the chamber a ; the piston D accordingly falls and with it the lever 

 H. Similarly an increase in the volume of the organ causes the lever to 

 rise. 



FIG. 88. KENAL ONCOMETER. Seen in section (semi-diagrammatic). K. kidney, 

 V. vessels and nerves imbedded in fat, &c. entering hilus of organ, O.C. and I.C. 

 outer and inner metal capsules screwed together by the screw S, and holding between 

 them the edge of the membrane M which applies itself to the surface of the kidney, 

 and forms with the metal capsule two chambers a and B, one of which (B) is closed 

 by a plug filling the opening B, while the other (a) communicates by a tube T with 

 the recording instrument. The other opening C (which is closed by a small tap) is 

 for the purpose of filling the chamber a with warm oil, after the kidney has been 

 placed in the box, the other chamber B having been previously partly filled, the 

 quantity introduced into it depending upon the size of the kidney. 



The volume of the kidney may be increased by a swelling of 

 its constituent cells and other structural elements, by an accumu- 

 lation of lymph in its lymph-spaces, and by a distension of its 

 blood vessels. Compared with the third, the two former causes 

 are in health so insignificant and problematical that they may be 



