DISEASES OF THE BRAIN. 475 



theory, enunciated first by Monro Secundus, and admitted 

 by Abercrombie, was supported by experiments performed 

 by Dr Kellie, who came to the conclusion, 



1st, That in the brains of animals that have died of 

 haemorrhage, there is no lack of blood, but, on the contrary, 

 very often a state of venous congestion. 



2d, That congestion of the cerebral vessels is not met with 

 in those cases in which we should most expect to find it ; 

 in persons, for example, who die strangled. 



3d, That the quantity of blood in the cerebral vessels is 

 not affected by gravitation ; in other words, that it remains 

 the same, whatever may be the posture of the body and 

 the position of the head. 



The above conclusions have been demonstrated to be 

 erroneous by Dr Burrows, who has shown that haemorrhage 

 has a most decided effect in depleting the cerebral blood- 

 vessels, and in reducing the quantity of blood within, as 

 well as upon the outside of the cranium. He has, more- 

 over, proved that " the principle of the subsidence of fluids 

 after death operates on the parts contained within the 

 cranium, as well as upon those situated in the thorax or 

 abdomen."* 



Dr Watson says, we fall back " upon another principle 

 whereby some of the difficulty and obscureness which 

 attend certain affections of the brain and nerves may be 

 explained I mean the principle of varying pressure upon 

 the nervous substance. 



" Physiologists say that the cerebral matter is incompres- 

 sible. This is another of the questionable assumptions 

 implied in the foregoing theory. Upon what grounds the 

 opinion may rest I am ignorant ; but whether the brain 



* Lectures on the Principles and Practice of Physic by Dr Watson. 

 Vol. i. p. 368. 



