APPENDIX. 387 



of the drums. An inverted cone outside the pulley ^D) reduces the chance 

 of the cord being liberated from (D) during the latter operation. 



The drums can be run in practically any position on their table, and they 

 can be removed from the latter without trouble, the gearing cords when not in 

 use being attached to hooks on the wall close to the shafting. The tables are 

 thus left completely free for other purposes. The drums are provided with a 

 starting and stopping contrivance (B) which is independent of the gearing 

 cord. The driving spindle, which carries the cone (D) and pulley (E), runs 

 in ball bearings in a rocking carrier which is tilted by the lever (B) either 

 into contact with or free of (F), a disc attached on the cylinder axle. This 

 axle is also on ball bearings. The drum can be readily adjusted for height 

 or removed for covering and smoking without stopping the driving spindle. 



The running parts are throughout the system either on centres or on ball 

 bearings. The resultant diminution of friction is so considerable that the 

 small motor already mentioned turns eight to twelve cylinders easily with a 

 25 -pound water pressure. 



The disc (F) has holes bored into its edge into which a pin or pins can be 

 fixed for making contact with (H) when automatic stimulation is required at 

 a definite epoch in the revolution of the cylinder. 



The stand (M)-^ lends itself to most experiments on frog muscle, nerve, and 

 heart. The bracket (P), adjustable on the pillar (N), will carry any ordinary 

 form of muscle-chamber, &c. , with slight adaptation. For the support of a 

 time-marker the "stirrup" (Q) is provided. This turned behind the 

 muscle-chamber will hold a rod u])on which the muscle-lever can be rested in 

 an after-load experiment, or to which a spring can be attached for the muscle 

 to pull upon in taking an isometric myogram. The same can be accomplished 

 with the stirrup in the front position by using a second clamp and bent metal 

 rod. 



The points of the writing-levers, after being adjusted by hand, can be finely 

 adjusted or lifted off the paper by means of the adjusting screw and lever 

 (0). Stability is conferred by the weight of metal in the stand (Birch). 



MICRO-CHEMICAL DETECTION OF GLYCOGEN, IRON 

 AND PHOSPHORUS IN VARIOUS CELLS. 



Glycogen in Liver Cells, — The essential part of this process is that, as 

 glycogen is soluble in water, the liver or other tissue supposed to contain the 

 glycogen must not be placed in icater. Feed a rabbit on carrots, and 5-6 

 hours afterwards kill it ; cut part of the liver into small pieces and harden 

 them in absolute alcohol. Cut hand sections, moistening the razor with 



1 Since this stand was devised about three years ago, Dr Birch has become acquainted 

 with the fact that Runne of Basle makes a stand of somewhat similar construction which 

 he calls the Basler stativ. 



