HARMONY IN MUSIC. 93 



investigation of the action of the senses, or have our 

 attention directed by illness to the phenomena of our own 

 bodies. Thus we often find patients, when suffering under 

 a slight inflammation of the eyes, become for the first 

 time aware of those beads and fibres known as mouche^ 

 volantes swimming about within the vitreous humour of 

 the eye, and then they often hypochondriacally imagine 

 all sorts of coming evils, because they fancy that these 

 appearances are new, whereas they have generally existed 

 all their lives. 



Who can easily discover that there is an absolutely 

 blind point, the so-called jpunctum ccecuin, within the 

 retina of every healthy eye ? How many people know 

 that the only objects they see single are those at which 

 they are looking, and that all other objects, behind or 

 before these, appear double ? I could adduce a long list 

 of similar examples, which have not been brought to 

 light till the actions of the senses were scientifically in- 

 vestigated, and which remain obstinately concealed, till 

 attention has been drawn to them by appropriate means 

 — often an extremely difficult task to accomplish. 



To this class of phenomena belong the upper partial 

 tones. It is not enough for the auditory nerve to have a 

 sensation. The intellect must reflect upon it. Hence 

 my former distinction of a material and a spiritual ear. 



We always hear the tone of a string accompanied by a 

 certain combination of upper partial tones. A diff*erent 

 combination of such tones belongs to the tone of a flute, 

 or of the human voice, or of a dog's howl. Whether a 

 violin or a flute, a man or a dog is close by us is a matter 

 of interest for us to know, and our ear takes care to dis- 

 tinguish the peculiarities of their tones with accuracy. 

 The means by which we can distinguish them, however, 

 is a matter of perfect indifference. 



Whether the cry of the dog contains the higher octave 



