of Voluntary Nervous Action. 193 
plain our appreciation of continuous sounds, as a musical tone ; 
if the vibrations occur at a less rapid rate than that they are 
recognized as separate sounds,—if at a higher rate as continu- 
s tones. 
4th. It is maintained by some writers upon purely meta- 
sciousness. is pulsation or vibration is, of course, very 
rapid ; otherwise, we should not have to infer its existence, 
but would know it by perceiving the alternation of one state 
with another. We may make it to some extent perceptible, 
as well as of vision, and during brief intervals not only does 
the object cease to be visible, but the mind seems to go out.” 
Dr. Spence may object to my “hypothesis” as a “ premature 
theory ;” however, his words express quite clearly my views, 
and seem to accord well with the facts in the case. 
Ithaca, N. ¥., July 1st, 1880. 
pine ae Hy ores Reopens considered as Negations, Journal of 
ssa hemes pose. Vou, XX, No. 117.—Sxpr., 1880. 
