8 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



gyri or the white matter beneath them were destroyed 

 or in any way thrown out of function, then, though you or 

 I might see the object, we should not know what it was, 

 because we should have no recollection of having seen 

 the object or of its use. The condition is called mind- 

 blindness. In a similar way mind-deafness arises from 

 dcsl ruction of the superior and transverse temporal con- 

 volutions on the left side. A perfectly familiar word 

 addressed to us would in that case be heard, but would 

 convey no meaning. In fact, we right-handed people 

 have got all these memories, the result of a lifetime of 

 observation and reflection, stored in certain parts of our 

 left brain. There is considerable evidence that the left 

 hemisphere is slightly heavier than the right (vide the 

 observations of Dr. Boyd* and of Brocat) ; Charlton 

 BastianJ also found the specific gravity of the grey 

 matter on the left side higher than that of the right. 



The speech centre convolutions are usually much more 

 developed on the left side than on the right, while in 

 left-handed men the reverse exists. 



The right-sidedness of man has no doubt been increased 

 by artificial means ; the child is always taught to use the 

 right hand in writing, drawing, in shaking hands and in 

 many other ways. So far as I have been able 1 to discover 

 right-handedness is the rule with all the races of man- 

 kind. It is an interesting question how long this 

 condition has existed. Linguistic evidence shews it to 

 be ancient, the curious association of the dexter hand 

 with intellectual and moral qualities, its symbolism of 

 that which is good, clever, favourable, or happy, occurs 



•Phil. Trans. Roy. Socy., 18G1. 



| Quoted l)v Bateman, Jour. Mental Science, Oct. 18G9. 



♦ Lancet, July 8, 1871. 



