1879.] Dr. Ord. Structure of the Spinal Cord. 265 



to be maintained in a fully oxidized state. A further advantage is 

 given by the influence of the presence of ammonia on the colour of 

 the test, for, in proportion to the height of colour of a volumetric 

 liquid, so is its degree of delicacy as a reagent, and the effect of the 

 addition of ammonia to the ordinary copper test is to considerably 

 increase the blue colour belonging to it. 



Seeing that the test here proposed acts with equal efficiency either 

 in the presence or absence of extraneous organic matter, it is alike 

 adapted for employment by the chemist, the physiologist, and the 

 medical practitioner in relation to diabetes. 



IV. "On the Effect of Strong Induction-Currents upon the 

 Structure of the Spinal Cord." By William Miller Ord, 

 M,D., F.L.S., Fellow of the Royal College of Physicians, 

 Physician to St. Thomas's Hospital. Communicated by J. 

 Simon, C.B., D.C.L., F.R.S. Received December 17, 1878. 



(Abstract.) 



The results of a series of experiments are related. They were 

 founded upon considerations offered by chorea, tetanus, and similar 

 diseases ; certain clinical facts and post-mortem observations having 

 led the author to suppose that the occurrence of protoplasmic convul- 

 sion or spasm in the grey matter of the nervous system was con- 

 sistent with the morbid appearances and with the history of cases. 



The present series of observations was made upon adolescent dogs. 

 The spinal cord was the part selected for experiment. The dogs were 

 killed by chloroform, and the cord, rapidly exposed, was galvanized 

 for different periods and in different directions. In all cases parallel 

 experiments were made with dogs of the same age and size, all points 

 of the operation being carried out in the same way, save for the appli- 

 cation of the galvanic currents. 



The following effects were observed : — 



1. Broadening of the cord in parts through which currents had 

 been passed longitudinally, narrowing where transverse currents had 

 been applied. 



2. In the narrowed parts a great diminution in the sectional area of 

 the grey matter with retraction of the posterior horns. 



3. In the same parts a remarkable dilatation of the central spinal 

 canal, and an infiltration of myelin and leucocytes into the cavity. 



4. The production of spaces around corpuscles, vessels, and nerve- 

 bundles by the retraction of the protoplasmic matter. Such spaces 

 were often found tilled with debris, containing coagula, myelin, and 

 vacuoles. They corresponded in appearance with the "perivascular 

 erosions " of Dickinson. 



VOL. xxviii. u 



