194 Dr. J. S. Lombard. On the Propagation of 



the outer surface of the scalp, a change of o, l C. on the surface of 

 the brain, in the animal in question. 



Table VIII.— Effects of 0°'l C. difference of temperature through 75 

 millims. of sheep's skull and 3 millims. of sheep's scalp, taken to- 

 gether. 1° of galvanometer is equal to 0°-0006742 C. ; and 0°'l C. 

 is equal to 148°'316 of galvanometer. 



Times. 



Averages. 



Maxima. 



Minima. 



Degrees 

 of 



galvano- 

 meter. 



Thermo - 

 metric 

 values. 



Degrees 

 of 



galvano- 

 meter. 



Thermo- 



metric 

 values. 



Degrees 

 of 



galvano- 

 meter. 



Thermo- 



metric 

 values. 



At the end of — 



1 min. 15 sec. 



2 „ „ 

 4 „ „ 

 6 „ „ 



2-767° 

 11-409 

 35-450 

 63-424 



•001866° C. 

 •007692 

 •023902 

 •042762 



4-971° 

 19-550 

 65-367 

 88-083 



•003352° C. 

 •013181 

 •044073 

 •059389 



0-931° 

 4-293 

 9-671 

 29-504 



•000628° C. 

 •002894 

 •006520 

 •019892 



Percentages of heat transmitted. 



Times. 



Averages. 



Maxima. 



Minima. 





1*866 per cent. 



7-692 „ 

 23-902 

 42-762 



3-352 per cent. 

 13-181 „ 

 44-073 

 59-389 



0-628 per cent. 

 2-894 „ 

 6-520 

 19-892 



2 „ „ 



4 „ „ 



6 „ „ 



Coming to the permanent thermal condition of the compound con- 

 ductor, we can estimate, in the same manner as we have just done, 

 from the separate tables for bone and skin, the amount of heat which 

 would be transmitted when this condition is reached. Table IX gives 

 the results of these estimates. Here, again, we have evidence that — 

 although diminished — the external manifestations of 0°"1 C. change 

 at the cerebral surface would still be amply great to admit of detec- 

 tion by much coarser instruments than those we are employing. 

 Supposing the rise of temperature at the cerebral surface to be only 

 o, 01 C, instead of 0°T C, it would still be plainly visible at the 

 exterior at the end of the fourth minute ; for the percentage of trans- 

 mission at this period would give a galvanometric deflection of 3° '545, 

 equal to o, 00239 C, while when the permanent thermal condition 

 was attained, the deflection would be 8 o- 603, equal to o, 0058 C. But, 

 as was stated in the introduction, there is no reason whatever why 



