r^, IliVICU. 



KxrEKlMENT 45. 

 A largo dog 



l>(Ar. M. -I Sccliou niiwliv 



3:15 W.28 



3^5 'IVotiiig nrli-riul prcMun* kIiowc ciiuiplctc imlny of ihe roiio-motor nj-stcm. 



/Ih/o/ihi/. — I'nrtiul wction just bt-low the point of lliu culuimis. 



Tlit'se cxjM'riiiU'Hts prove lliat severe injuries of the nudiillu IkIow tlie cul.imus 

 produce results similar to but greater than tliose caused by section of the cord, 

 namely, fall of the animal tem[)erature and of the arterial pressun-, and confirm 

 the belief that the fall of temperature is due to vaso-motor paralysis. 



The efl'ects on the dissipation and production of anim;il luat of injury either 

 in the immediate neigiiborhood of, or below the vaso-motor centre having been 

 determiiu'd, attention naturally next directs itself to tiu' results produced by 

 wounding the medulla so far above the vaso-motor centre as to avoi<l injuring it. 



Tscheschichin, in a single cxiu'rimenf, fouiul that division of the nu-didla at ita 

 junction with the pons was followed by an immediate and very marki-d rise of the 

 temperature of the body. .1. l$ruck and .\. Giinter {fyiiii/cr^s Arc/iir, Bd. iii. p. 579) 

 have also experimented upon the effect of section of the medulla oblongata at the 

 border of the pons on the temperature. They used rabbits, ami operated without 

 opening the skull. In seven operations they found that in one the temperature rose 

 enormously after the section, in another it rose very decidedly (l°.l C.) and in four 

 cases it fell continuously, 



I have myself practised a number of experiments of this character, in most cases 

 upon dogs, but in u few instances upon rabbits. I have found it a matter of diffi- 

 culty to make a clean, complete section of the medulla at its junction with the pons 

 without inducing serious hemorrhage or injuring some other portion of the medulla. 

 Tlu; chief trouble lies with the bleeding. The various venous and arterial anasto- 

 moses at the base of the brain are always in great danger, and the slightest injury 

 to them invalidates the experiment by causing pressure on the vaso-motor, respira- 

 tory, anil otlier important centres. Various methods of experimenting have been 

 practised. Thus, I have tried entering laterally, boring through the skull with a 

 suitable knife, or opening it with a trephine. Again, various attempts have been 

 made to enter through the foramen magnum. At one time a knife, invented by Dr. 

 Ix'iutenbach, acting somewhat on the ])rinriple of Bellocque's eanula, was employed; 

 the eanula being passed up along tlu" nudulla through the foramen mngnuni, and 

 the knife pushed out when sufficiently far in. .\ thorough trial demonstrated that 

 this plan is impracticable. .Ml otliir methods of operating were finally abandoned 

 for the following: — 



With a small trephim- .ip. n the skull in the triangular space Ix low the occipital 

 protulM>rauce, so as to enter between the diverging luanehesof the great longitudinal 

 sinus. Then hnvc the head of the animal firmly held vertically with the nose 

 downwards, pu.ss a narrow dull-pointed knife in, and when sufiicieiitly entered bend 



