CHAP, in.] ELIMINATION OF WASTE PRODUCTS. 689 



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, etc. 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 K (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. BENAL ONCOMETEK. Seen in section (semi-diagrammatic). K. kidney, 

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

 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 



