ZOOLOGY. 335 



entirely regulated by physical conditions, c. A genus has dissimilar 

 or only partially comparable relations with time and space, and occu- 

 pies areas in both, having only partial relations to physical conditions. 

 The investigation of these distinctions and relations form the subject 

 of a great chapter in the philosophy of natural history. That 

 philosophy contemplates the laws that regulate the manifestation of 

 life exhibited in organized nature, and their dependence upon and 

 connection with the inorganic world and its phenomena. None 

 teaches more emphatically the difficulties with which man's mind 

 must contend, when attempting to comprehend the wisdom embodied 

 in the universe, and none holds out a more cheering prospect of future 

 discovery in fresh and unexpected fields of delightful research. 



OX THE STATE OF THE MIND DURING SLEEP. 



AT the British Association, Dr. Fowler read a paper on the ques- 

 tion, " what is the state of the mind and vitality during perfect sleep 

 and the sleep in which we dream ;" the object of the paper was to 

 show that mind was a force similar to light, heat, and electricity, 

 and that the body was the means by which it made itself apparent. 



Prof. M'Cosh said that he should like to see the Section divided, so 

 that the speculative or transcendental portion of it might be distinct 

 from the rest. He was of opinion that Dr. Fowler had gone far 

 beyond the facts of physiology. It was, of course, quite true that 

 mind has a power over matter, and in that respect it might be describ- 

 ed as a force, but it is a force very different from the physical forces 

 with which it had been compared. Mental power did not require a 

 4 coil,' and in this sense it was very different from electricity or grav- 

 itation. Sir D. Brewster said that a friend of his was at present busy 

 investigating on the subject of Dr. Fowler's paper. He fixed his atten- 

 tion on a certain object ; and, by marking the time with a watch, 

 recorded his sensations between the period of perfect wakefulness 

 and profound sleep. It might be mentioned, as a fact, that different 

 parts of the body fall asleep at different times; and it might, perhaps, 

 be argued by analogy that different parts of the brain fall asleep at 

 different times. It was a fact equally well known, that different parts 

 of the body get intoxicated sooner than others. First, the eyes begin 

 to glaze, then the tongue to get flabby, then the muscles begin to give 

 way in the arms, then in the limbs, and so on. Experiments had also 

 recently been made to ascertain the different sensitiveness of various 

 parts of the human body, by means of a pair of compasses. At a dis- 

 tance of only one-eight of an inch between the legs of the compasses, 

 the two points will be distinguished on some parts of the body, whilst 

 on the back the effect will be that of only one point, unless the com- 

 pass is stretched several inches. 

 29* 





