■ Notes: ii. 7. 167 



easy to ridicule A.'s view, and ridicule has not been spared. But to me A.'s theory, 

 erroneous as it was, seems an honest and ingenious attempt to colligate hypothetically 

 and in a presentable form such facts and supposed facts as Were known to him or 

 accepted by him. We now know that the brain and not the heart is the sensorium 

 commune ; allowing for this fundamental error the view of A. agrees with the modern 

 views, in attributing sleep to an alteration, quantitative and qualitative, in the blood- 

 supply of the sensorium, and in finding a similarity between sleep and epilepsy. A. held 

 that the amount of blood in the sensorium was increased, and until quite recently, when 

 Mr. Durham and others showed by actual inspection that this Was not so, but that in 

 reality there was diminished vascularity, physiologists as a rule were of the same opinion. 

 A. thought the qualitative change was due to additional impurity, modem conjecture 

 points to exhausted oxygen. As regards the relation of sleep to epilepsy, ** nous pouvons 

 meme dire," says Brown Sequard,'*' que chez beaucovp de personnes lion dpileptiques le 

 sommeil ressemble a une legere attaque d'epilepsie " {Le(ons sur les nerfs vasomoteurs, 

 p. 121). . . • 



16. Cf. Note 8. 



17. Cfv ii, 4, Note 10 ; ii. 10, Note 18. 



18. That man's brain is heavier than that of other animals in proportion to his weight 

 is- true with very few exceptions, which are. furnished by certain species of small birds, 

 monkeys, and rodents, whose body is lean and therefore light {Cuvier, An. Comp. ii. 419). 

 Leuret gives the following general results ; in fishes the brain is to body as I to 5668 ; in 

 reptiles as I to 1321,. in birds as I to 212, in mammals as I to 186. But in man the brain 

 forms from t'ir to ^ of the whole weight. . ' ' 



Whether man or woman has the larger brain in proportion to- the body is a question not 

 satisfactorily settled ; for observers have arrived at different results. Thus Dr. Peacock 

 in one set of observations ^Monthly Joiirn. Med. Sc. vii. 1847) found the encephalon in 

 • women in the proportion to the body of i : 33'5 ; that of man I : 37 "2 ; that is he found 

 the female braiii the heavier in proportion to the whole weight. In another set however 

 {Path. Tr. xii. ) he found the proportions I : 3273 in the male, and'i : 39 in the female. 



The actual weight of ths brain of womenis, on an average, about 5 ounces less than 

 that of men, 



19. The slight differences of temperature betweeii one warm-blooded animal and. 

 another cannot be estimated by touch ; and as A. had no thermometer his statements in 

 the text are but guesses, and unlucky guesses.- (See however ii. 6, Note 7, and Introd. 

 p. xxiii.) For all or most birds, and not a few mammals, are hotter than man, Neither 

 again is man hotter than woman : the differences in this respect being apparently 

 independent of sex ; or the ballnce being in favour of woman. Thus in a long series 

 of observations made by me on a man and woman, the temperature of the latter was 

 notably higher than that of the former {Diurnal variations of the tempirature of the 

 huvian body in health, St. Georgis Hospital Reports, i.). Wunderlich also concludes from 

 such insufficient observations as exist that the temperature in adult women is slightly 

 higher than that of man {Eigenwiirme, etc. 2nd.ed. p. 104). 



The reasons why A. considers the male to be hotter than the female are set forth in De 

 Gen. iv. i, 27. ' • 



20. The meaning- is : heat promotes growth ; and as heat mounts upwards from its 

 source, i.e. the heart, growth will be promoted in the upward direction in preference to 

 any other. Cf. iv. 10, Note il. That heat mounts upwards is of course A.'s mode of 

 viewing such facts as the ascent of hot air, and the upward pointing of flame, etc. Cf. ii. 

 I, Note 2. 



