( 340 ) 



differences, both ;is to their extent, shape and boundaries and as to 

 the intensity of th^ phenomenon itself. Usually the field, in which 

 the hair rose, was nearly rectangular, and save tor a slight 



deviation caudal-ward, it was lying vertically on the mid-dorsal line. 

 In the most successful experiments the pilo-inolor areas extended nearly 

 unto the dorsal axilla-inguinal line over a dorso-ventral surface of 

 almost 60 m.M. The cranio-caudal breadtli amounted on the average 

 to 26 m.M. For an instance of the proportions of the pilomotor 

 areas in an exceptionally favourable case I refer to the photographs 

 represented in fig. 6 and 7. 



The isolated sensible areas usually presented a shape not greatly 

 different from that of the pilomotor areas described above. Like these 

 they were generally nearly rectangular, lying almost vertically on the 

 mid-dorsal line, and they showed likewise a slight deviation caudal- 

 ward, perhaps even somewhat more marked. Cranially and caudally 

 they were bounded by the insensible areas; ventrally they passed 

 without any distinct boundaries into the lateral part of the body, 

 where sensibility was retained wholly intact. The cranio-caudal 

 breadth of' the sensible areas was on the average 30 m.M., their 

 dorso-ventral extent of course was not lo be defined; that of the 

 insensible areas was on the average 60 m.M. 



We may now pass on to a comparison between the sensible and 

 (lie pilomotor skin-areas. On account of what I remarked before 

 about the variability both as to shape and extent of these latter ones, 

 it may be inferred already that the results of this comparison presented 

 likewise great differences. On one important point however the results 

 of all my experiments are in accord : the pilomotor skin-area was 

 always to be found within the sensible area of the isolated nerve- 

 branch. In this respect the principal problem I had put before me 

 in all my experiments, may be considered to have been solved, at 

 least for that portion of the skin of the trunk on which I made my 

 experiments. As regards further the relative extent of the sensible 

 and of the pilomotor skin-areas, and the exact situation of the latter 

 within the former, I found, as remarked before, great differences. 

 Sometimes the pilomotor field area had an extent nearly equal to 

 that of the sensible field, both fields being consequently almost 

 identical. In the majority of cases however the pilomotor skin-area 

 was less extensive in all directions than the sensible area. The place, 

 occupied by the pilomotor field within the sensible field differed 

 greatly in different cases. Generally it was lying almost in the midsl 

 of it, as is shown in the cats, photographies of which are represented 

 in tig. 8 and 9. 



