564 Dr. A. E. Wright. On the Leucocytes of Peptone [Feb. 9, 



experiments. Anatomical evidence is at present so scanty regarding 

 afferent nerve fibres from muscle that investigation of their ana- 

 tomical relation seems absolutely requisite for examining the 

 problem further. 



[Just as the lumbo-sacral region of the cord may be split along the 

 median plane without interference to the jerk of either side,* so the 

 same may be done without hindering the above ascending reflex 

 abolition of the jerk. Extinction of the jerk by exciting the central 

 end of the 8th root (from hamstrings) affects the jerk four segments 

 higher without in that distance spreading over to the opposite side. 

 But the excitation affects the jerk of the opposite side if the scope of 

 a considerable length of cord be allowed it. If in the Cat the cord be 

 transversely divided at the llth thoracic segment, excitation of the 

 afferent fibres from a hamstring muscle of one side (e.g., right) applies 

 chiefly to the jerk on the same side (right), but also to the jerk on 

 the opposite. If, however, in the Cat (in which jerk belongs to the 

 6th and 5th lumbar segments) the cord be transversely cut at or 

 below the 3rd, the extinction from the hamstring nerve is confined to 

 the same side only. In other words, the presence of additional higher 

 segments seems requisite before the passage of the impulses in 

 question across the median plane of the cord, a fact in curious 

 harmony with an observation by Hallstenf regarding the elicitation 

 of " crossed reflexes " in the frog. The median posterior column 

 between the 8th and 4th lumbar levels can be removed in toto without 

 impairing the influence of the hamstring nerve on the jerk. It is 

 clear also that those fibres of the posterior root which pass to Clarke's 

 column cannot be the requisite afferents, either from the extensor or 

 flexor thigh muscles, because the jerk and the above-described extinc- 

 tion of it are unaffected in the Cat by transverse section of the cord 

 just below the 4th lumbar segment, i.e., the segment where Clarke's 

 column stops short. February 8, 1893.] 



HI. "On the Leucocytes of Peptone and other Varieties of 

 Liquid Extravascular Blood." By A. E. WRIGHT, M.D., 

 Professor of Pathology, Army Medical School, Netley. 

 Communicated by A. D. WALLER, M.D., F.R.S. Received 

 January 30, 1893. 



In the course of some investigations on the subject of blood- 

 coagulation, I was led to enumerate the white blood corpuscle* in the 

 fterent varieties of extravascular blood. I propose to report the 



* Sberrington, ' Journ. of Physiol.,' vol. 13, p. 666. 

 t ' Archiv f. Physiol.,' 1885. 



