REPORT ON ANIMAL MAGNETISM. 153 
for example, that some people are absolutely blind to cer- 
tain colours, as red, and enjoy perfect vision relatively to 
yellow, to green, and to blue. If the Newtonian theory 
of emission be true, we must irrevocably admit that a ray 
ceases to be light as soon as we diminish its velocity by 
one ten thousandth part. Thence flow those natural con- 
jectures, which are well worthy of experimental exam- 
ination: all men do not see by the same rays; decided 
differences may exist in this respect in the same individ- 
ual during various nervous states ; it is possible that the 
calorific rays, the dark rays of one person, may be the 
luminous rays of another person, and reciprocally ; the 
calorific rays traverse some substances freely, which are 
therefore called diathermal, these substances, thus far, 
had been called opaque, because they transmit no ray 
eommonly called luminous ; now the words opaque and 
diathermal have no absolute meaning. ‘The diathermals 
allow those rays to pass through which constitute the light 
of one man; and they stop those which constitute the 
light of another man. Perhaps in this way the key of 
many phenomena might be found, that till now have re- 
mained without any plausible explanation. 
Nothing, in the marvels of somnambulism, raised more 
doubts than an oft-repeated assertion, relative to the 
power which certain persons are said to possess in a 
state of crisis, of deciphering a letter at a distance with 
the foot, the nape of the neck, or the stomach. The word 
impossible in this instance seemed quite legitimate. Still, 
I do not doubt but some rigid minds would withhold it 
after having reflected on the ingenious experiments by 
which Moser produces, also at a distance, very distinct 
images of all sorts of objects, on all sorts of bodies, and in 
the most complete darkness. 
7* 
