1020 RATIONALE OF SPASMS. 



want of good arterial blood in the brain, is mani- 

 fest from the purple or livid hue of the face, 

 shewing that, even in the arteries, the blood is 

 black ; consequently, that respiration is nearly 

 or quite suspended during the paroxysm. 



In all cases, the more suddenly the brain is 

 deprived of good arterial blood, and its power of 

 commanding the movements of the muscles de- 

 stroyed, the more violent is their spasmodic action. 

 For it must be remembered, that as the brain 

 receives about five times more blood in a given 

 time than an equal weight of the body in general, 

 its power is abolished sooner by whatever dimi- 

 nishes the chemical function of the lungs, and 

 the force of the circulation, than that of the 

 muscles, which continue to contract for some 

 time after the power of the brain has ceased, 

 independent of its guidance, and therefore in a 

 spasmodic or involuntary manner. The brain of 

 infants is also much larger, and receives more 

 blood, in proportion to the size of their bodies, 

 than adults, which is the reason they are more 

 liable to spasmodic affections. 



For example, in cases of decapitation, the 

 muscles contract with more or less violence until 

 their vitality is extinguished, which proves 

 clearly that spasms are " not owing to a vigorous 

 influx of nervous influence into them from the 

 brain," as supposed by Boerhaave and other 

 pathologists, nor to " an increased activity of 



