378 Dr. J. Burdon-Sanclerson and F. J. M. Page. [May 13, 



on the cooler surface, and a series of rheotome observations are made 

 during the 2nd second, it is observed that the deflections of the ter- 

 minal phase are diminished. In the contrary case they are increased 

 and begin at an earlier period ; so that, at a time at which the sur- 

 faces m and / were before isoelectrical, the surface m is now positive 

 to/. To produce these effects a difference between the temperatures 

 of the chambers of only 3° is sufficient. That which exists between 

 the led-off surfaces is obviously much less. 



If, in the manner described in our previous paper, the surface of the 

 ventricle is temporarily warmed by the passage for a second or two of 

 a voltaic current through a platinum wire fixed in the neighbourhood 

 of one of the contacts — say the contact m — similar but much more 

 considerable effects are produced, which, when observed with the aid 

 of the rheotome, exhibit the characters shown in the table. 



Table III. 



Time after excitation, at 

 which the galvanometer cir- 



0-2 



ii 



0-4 



0-6 



0-8] 



1-0 



1-2 



1-4 



1-6 



1-8 



ii 



2-0 



Preliminary observation before 



-30 



















+ 5 



+ 23 



+ 20 



+ 5 







Immediately after warming ... 



-24 



+ 17 



+ 30 



+ 71 



-f 95 



+ 99 



+ 63 



+ 9 



+ 5 









-25 



+5 



+ 2 



+ 9 



+ 25 



+ 55 



+ 52 



+ 6 



+ 2 







24 seconds later 



-29 















+ 6 



+ 14 



+ 50 



+ 9 



+ 2 























+ 2 



+ 7 



+ 34 



+ 14 



+ 5 



























+ 5 



+ 24 



+ 16 











The table represents, first, the results of a series of preliminary 

 observations, showing the electrical state of the surfaces during ten 

 successive periods after excitation when their temperatures were 

 equal ; and, secondly, ten series of observations relating to the same 

 ten periods, showing the condition of the same surfaces at various 

 intervals of time after warming. We learn from it (1) that in the 

 unexcited state the revolution of the rheotome, i.e., the closure of the 

 galvanometer circuit, is without effect on the needle, whether the tem- 

 peratures of the two surfaces are equal or not ; (2) that in the excited 

 state the needle remains unaffected during the isoelectrical interval 

 only in case the temperatures are equal. If they are unequal the 

 warmer of the two tends to become positive to the cooler, the electrical 

 difference between them increasing and diminishing with the difference 

 of temperature. It is to be noticed that this effect manifests itself 

 first at the end of the isoelectrical interval, over which it gradually 

 extends as the difference of temperature increases. 



3. Time-relations of the Variation in the Injured Ventricle.— ha. our 

 former paper we gave an account of the influence of slight injuries of 



