Apoplexy and Softening of the Brain. 85 



nomena are concerned, we must allow that apoplexy may arise 

 from any sudden pressure on the brain substance. Pagenstecher 

 produced the symptoms of the disease by injecting, at a regulated , 

 pressure, melted wax and tallow between the skull and dura 

 mater in the dog. In the moderate cases there were drowsiness, 

 psychic depression and general muscular weakness. In the more 

 severe ones there were added sleep and unilateral paralysis. In 

 the more extreme cases death followed in a few hours after coma 

 set in, though in some of these a partial recovery ensued if the 

 waxy mass was scooped out before the fatal symptoms appeared. 

 Cases ended fatally only when the injection pressure equalled 

 that of the blood, and convulsions occurred only when the pres- 

 sure was unsteady. The temperature fell as it does in apoplexy 

 in man, at the outset, but it continued falling to the fatal issue 

 contrary to what takes place in man. 



Duret injected water into the cranium of animals so as to pro- 

 duce great tension of the occipito-atloid membrane causing there- 

 by arrest of the respiration and slowing of the heart's action. On 

 tearing thCvmembrane so as to allow escape of the water, respira- 

 tion began anew and consciousness was gradually restored. 



Edes sustains the view^ that apoplexy is directly due to anaemia 

 of a lesser or greater portion of the brain substance, and that this 

 need not be in any one particular seat nor of any definite extent. 

 This anaemia is usually induced by pressure and may be caused 

 by effused blood, or serum, or by the extreme congestion due to 

 narcotic poisons, or other cause. Embolism of a cerebral vessel, 

 however, by cutting off the blood from the part of the brain 

 which it supplies may give rise to the apoplectic phenomena. 



Friedberger and Prohner found apoplexy quite frequent in 

 sheep, ox, and dog, and rare in the horse, although more subject 

 to the violent exertion which they put in the front of all causes. 

 It is probable that the sluggi,sh, pampered life of the first three 

 aniinals, and the tendency to fatty degenerations and heart disease 

 introduces a special predisposition as it does in man, while the 

 horse, inured to an open air life and a vigorous muscular condi- 

 tion, is comparatively immune. Bright' s disease is a common 

 cause in the human subject, with its resulting cardiac hypertrophy. 

 The degenerations attendant on these conditions and especially 

 fatty change (atheroma) in the walls of the cerebral arteries. 



