194 
DR. F. SBMON AND MR. V. HORSLEY ON AN INVESTIGATION 
with warm water or normal salt solution shock was in very great measure avoided. 
This was also provided against in the usual way with hot vessels, coverings, &c. 
In no case was the dura mater opened until immediately before the commencement 
of the excitation. 
The animal was then fixed on its side so that when the anterior wall of the trachea 
Irad been removed a perfect view from below Avas obtained of the vocal cords in their 
whole length. 
In all tins preparation of the trachea, larynx, &c., special care was necessary to 
avoid injury of the recurrent laryngeal nerves. Between every period of the excitation 
of the cortex it was douched with ^v'arm water or saline solution, protected by the 
skin-flap from the air and kept warm with hot sponges. 
Corona Radiata. —The investigation of the corona radiata of course enables one to 
decide many points concerning the amount of representation of various functions in 
the cortex. Naturally, however, the excitation of the few fibres descending from the 
conn)aratively extensive area of the cortex is not easy unless the electrodes be placed 
exactly upon the cut ends of the fibres. It is for this reason, no doubt, that a stronger 
stimulus'"" is usually required to successfully excite the fibres. The removal of the 
cortex was always efibcted by a single incision with a sharp scalpel at right angles to 
the supposed direction of the fibres. 
Interned Capside .—This was exposed by horizontal section through the hemisphere 
in the same way as that just described for the corona radiata. The line of the incision 
taken is referred to on p. 202, and the only point noteworthy here is the arrest of 
hsemorrhage, &c. Naturally bleeding comes almost entirely from the middle cerebral, 
the lenticulo-striate arteries and their branches. Bleeding from these vessels can be 
certaiidy arrested if a fragment of amadou be gently pressed on the open mouth of 
the vessel and left there. Usually the various bundles of fibres in the capsule w^ere 
then explored with the electrodes, and finally a careful transcript of the surface 
of the section made with compasses upon paper ruled with squares of 1 mm. a side, 
and the corresponding bundles of fibres indicated by arbitrary numbers placed on the 
squares into which the capsule was by this means divided. 
lli.e Medulla Oblongata .—This was exposed for excitation by reflecting the muscles 
and periosteum by the usual T-shaped incision from the occipital bone and the dorsal 
surfaces of the arches of the first two vertebrae without injury to the vertebral vessels. 
These same arches and the neighbouring portion of the occipital bone were then cut 
away with bone forceps. The dura mater was then divided in the middle line 
and the middle lobe of the cerebellum slightly drawn upwards or a portion removed in 
order to expose the lower end of the fourth ventricle. A drawdng was then made with 
compasses of the surfaces of the ventricle thus exposed on the 1 mm. ruled paper. 
Oozing from the cerebellar vessels was always readily controlled, even in the dog, by 
irrigation with hot water or saline solution. This had a very notable eflect also in raising 
* Putnam, Franck. 
