DESCRIPTION OF PLATES. 



PLATE I. 



The completed apparatus for measuring the production of animal heat and of carbonic acid : the 

 arrows show the directions of the air currents during action, p = exhaust pump, vi = general 

 meter. I = tube thermometer, y — exit tube from the calorimeter. a= inner box of calori- 

 meter. X = ingress tube of calorimeter, z = tube through which sample of air coming from 

 the calorimeter is taken, s = calcium bulbs for absorbing moisture. 6 = barium lubes for ab- 

 sorbing carbonic acid, m' = sample meter, v = aspirators. 



PLATE II. 



Fig. 1. — Transverse section of calorimeter, a = inner bo.x. w = water surrounding inner box. 

 X = clasps to bold down the iuuer box, also clamps of the lid. s = sawdust in which inner 

 box is packed. 



Fig. 2. — End of the inner box of the calorimeter. A = door. b = thumbscrews securing the door. 



Fig. 3. — Inner surface of the lid to the calorimeter, a = wire, which when in position is imbedded 

 in the soft rubber, c = openings for outlet and inlet tubes. Y ^= openings for the thermo- 

 meter. X = openings for the stirrer. 



Fig. 4. — Tracing of Experiment 104, p. 150. The irregularit}' of this and the other tracings ujion 

 this plate is due to defects of'the instrument with which thej were made. At tlie time it was 

 the only kyraographion at my disposal, and the drum was very irregular in its rotation. The 

 tracing shows, however, sufficiently well the effects of irritation of the Hitzig's brain region after 

 section of the vagi, curarizaiion and artificial respiration. At 11:25:30 (-|-) a mild galvanic 

 current was passed through the regions spoken of: at 11:20 (-f) this current was made very 

 powerful: at 11:27 it was withdrawn. The rise of pressure at 11:26 was due to dispersion of 

 the very powerful current and irritation of the trigeminal twigs in the brain membranes. 



Fig. 5 — Tracing of Experiment lOG, p. 151. This tracing portrays the result of destroying with a 

 needle the Ilitzig's regions in the cortex of the brain. The mechanical irritation caused no 

 rise of pressure, and the destruction no fall. Artificial respiration and curarization employed. 



Fig. 6.— Tracing of Experiment 100, p. 151. This tracing shows the effect of a very strong 

 current sent through the Ilitzig's region of the brain. It is so marked as not to need cxplaua- 

 tioQ. Artificial respiration and curarization employed. 



PLATE III. 



Fig. 1.— Tracing of Experiment lOT, p. 154. This tracing represents the effect of galvanizing the 

 sciatic nerve after section of the par vagum and destruction of the Ilitzig's region, curarization 

 and artificial respiration being practised. At the first -f the irritation was applied, at the 

 second + it was withdrawn. The current was of the same power as in Fig. 2, with which Fig. 1 

 should be contrasted. The two tracings were from a dog, in different stages of one experiment 

 33 October, 1880. ( *0T ) 



