324 



MESSRS. F. GOTCH AND V. HORSLEY 



annexed woodcut (fig. 6), in which two records, one of the muscle, the other of the 

 movement of the electrometer, are contrasted. The lower tracing, G, is that of the 

 muscular movements of the rectus femoris of the Cat ; the upper, E, is that of the 

 movements of the projected image of the mercurial meniscus of the electrometer 

 photographed on a sensitive plate. The juxtaposition of the records was effected by 

 a photographic reduction of the two tracings. It is necessary to point out that exact 

 comparison is not possible, since the two records were obtained from different animals ; 

 they are, however, comparable in this sense, that since we have selected in each case 

 fits of about the same degree of intensity, the general fused character of the first 

 stage, and the interrupted character of the second stage, is similar in each. 



Further, the change in character of the interrupted stage itself as the fit draws to 

 its close is very noticeable, the great increase in the extent of each clonic spasm 

 accompanying the slower rhythm is, as will be seen, a feature common to both records. 



It will now be advisable to consider in more detail the character of these electrical 

 variations. 



A reference to the photograph of the movements of the electrometer, in fig. 6, 

 will show that the first stage of the effect produced in the cord by exciting the 

 cortex, i.e., the tonic variation lasting during the period of excitation, is a complete 

 fusion of impulses, so that it is with our present instruments impossible to detect 

 any waves or intermissions in it. In this respect the tonic stage exhibits no 



Fig. 6. 



E. Photograph of movements of electrometer. 

 G. Tracing of contracting muscle. 

 t. Tracing of time signal with intervals of T Vth sec. 



difference from the tonus obtained by exciting the corona radiata after the cortex 

 is removed. It is otherwise with the graphic method, see p. 273, in which a 

 rhythm or period can be seen, showing the tonus to be an imperfect fusion of 

 contractions. Until the question is re-examined with still more delicate instru 

 ments, it must be left entirely open, as the absence of intermittence in the 

 electrical record may be due to instrumental inadequacy. We cannot, however, 

 refrain from suggesting that it may be possibly a genuine phenomenon, and that 

 the waves seen often on the tetanus curve, in the graphic method, may be in 

 relation with blocks in the motor path ; one such block we have found to be offered 



