720B NERVOUS SYSTEM. (NERVOUS CENTRES. ABNORMAL ANATOMY.) 



chronic inflammation. The softened condition 

 of the brain is doubtless due to a similar cause, 

 the blood yielding vitiated materials for the 

 nutrition of the organ. In brains of this de- 

 scription the dilated and congested state of the 

 veins, and the enlarged and lax condition of the 

 arteries, abundantly demonstrate how sluggish 

 had been the force by which the circulation is 

 maintained in the capillaries, that force of at- 

 traction between the blood and the nervous 

 matter, by which more than by any other means 

 active nutrition is maintained. 



The parts in which softening when partial is 

 apt to occur in the brain may be thus enume- 

 rated according to the order of their frequency 

 the fornix and septum lucidum, the corpus 

 striatum and optic thalamus, the mesocephale, 

 the corpus callosum and other transverse com- 

 missures, the hemispheres of the brain, the 

 cerebellum, the medulla oblongata. 



Of the inflammatory or red softening. 

 Another form of softening of less frequent oc- 

 currence than that just described possesses very 

 distinctive characters. It is generally pretty 

 circumscribed in extent, of a diffused redness, 

 most commonly of a bright hue; the consistence 

 of the part is much diminished, and it readily 

 breaks up under the stream of water. Nerve 

 tubes are found in it, more or less varicose and 

 friable, also red particles of the blood, and many 

 of those large nucleated cells commonly known 

 as exudation corpuscles, within which an active 

 molecular motion may be often seen. 



The red colour of this form of softening is 

 due partly to the injection of the bloodvessels, 

 and partly to the extravasation of the red parti- 

 cles of the blood throughout the softened part. 

 Sometimes the red colour is absent, although 

 the lesion is essentially the same. In such cases 

 the colour may be yellowish and due to the 

 presence of a less injection of the bloodvessels 

 and a slighter extravasation of the colouring- 

 matter of the blood. Dr. Bennet states that he 

 has found exudation corpuscles in a softening of 

 a brilliant white colour, a fact which seems to 

 indicate that the products of inflammation may 

 be present without discoloration, and that all 

 instances of white softening ought not to be 

 considered non-inflammatory. 



The researches of Dr. J . II. Bennett, of Edin- 

 burgh, are among the most important contribu- 

 tions to the morbid anatomy of the brain of late 

 years. I think he has clearly established that 

 the great characteristic of inflammatory soften- 

 ing is the presence of exudation corpuscles 

 about the minute vessels, and among the ele- 

 ments of the softened cerebral tissue. This is in 

 in the vast majority of instances accompanied 

 with discoloration, which sometimes is due 

 solely to the dark colour of the exudation cor- 

 puscles themselves. When these corpuscles 

 are not present, and especially when the soft- 

 ened portion of brain is free from colour, then 

 we must regard the lesion as non-inflammatory, 

 the result of imperfect nutrition, or as produced 

 by physical causes coming into operation shortly 

 before or after death. As the same process of 

 ' softening which involves the cerebral structure 

 often extends to the minute vessels, small extra- 



vasations, constituting the capillary apoplexy of 

 Cruveilhier, frequently occur where no indica- 

 tions of inflammation exist ; in such instances the 

 softening, although non-inflammatory, may be 

 of a yellow colour from the effused colouring 

 matter of the blood. 



1 cannot agree with Dr. Bennett in regarding 

 white softenings as generally post mortem, and 

 the result of maceration in serum. The soften- 

 ing of very thin parts, such as the fornix and 

 septum lucidum, no doubt, is frequently of this 

 character. But I have seen many instances of 

 white softening of other parts of the brain 

 which were not exposed to the physical condi- 

 tions calculated to produce such a change of 

 consistence. 



Inflammatory softening occurs most fre- 

 quently in parts which are near the great vascu- 

 lar surface of the pia mater ; the convolutions 

 and the white matter of the centrum ovale, the 

 corpus striatum, and the optic thalamus are the 

 most common situations of this lesion. In 

 thirty-three cases collected by Durand-Fardel 

 the softening was situated in the convolutions in 

 thirty-one, and in nine of them the convolutions 

 were the sole seat of softening. The following 

 table will illustrate the statement above made ; 

 it represents the results of fifty-three cases col- 

 lected from different sources. 



Convolutions and white substance 22 



Convolutions alone 6 



White substance alone 5 



Corpus striatum and optic thalamus 6 



Corpus striatum alone 11 



Optic thalamus alone 4 



Pons Varolii 3 



Crus cerebri 1 



Corpus callosum 1 



Walls of the ventricles, septum ...... ^-. .... 1 



Fornix 1 



Cerebellum ..... . . 1 



Suppuration. From what has been stated in 

 the previous paragraphs it is plain that the most 

 important sign of inflammation of the brain 

 is red softening. Infiltration of pus is rare. 

 Dr. Bennett states that in no single instance of 

 numerous examinations made by him could 

 softening be traced to the presence or infiltration 

 of pus. This is a direct refutation of Lalle- 

 mand's assertion that this form of softening owes 

 its colour to the infiltration of pus. Pus, how- 

 ever, is sometimes collected into a cavity in the 

 brain, forming an abscess. An excavation of 

 greater or less size is formed in the substance of 

 the brain, and this is lined by a yellowish mem- 

 braniform layer, which resembles either lymph in 

 an expanded form, or the purulent matter itself 

 in a less liquid form, compressed into the form 

 of a membrane by the accumulated liquid. 



Pus in the brain is of slow formation, and 

 has often become collected in considerable 

 quantity before it betokens its presence by any 

 symptoms. Sometimes we have the opportu- 

 nity of examining it before it has acquired the 

 yellow colour and oily consistence of laudable 

 pus. In this stage it may be mistaken for some 

 malignant formation ; it is whitish, semi-solid, 

 and sometimes mixed with streaks of blood. 

 Its true nature may be recognized by micro- 



