Address of A. R. Wallace at the Glasgow Meeting. 363 
ora very dark coloration. Thus in the Moluccas and New 
Guinea alone we have bright red parrots belonging to two dis- 
tinct families,* and which, therefore, most probably have been 
independently produced or preserved by some common cause. 
Here too and in Australia we have black parrots and pigeons ;t 
and it is a most curious and suggestive fact that in another 
insular sub-region—that of Madagascar and the Mascarene 
Islands—these same colors reappear in the same two groups.} 
Some very curious physiological facts bearing upon the pres- 
ence or absence of white colors in the higher animals have 
lately been adduced by Dr. Ogle.§ It has been found that a 
colored or dark pigment in the olfactory region of the nostrils 
is essential to perfect smell, and this pigment is rarely deficient 
except when the whole animal is purely white. In these cases 
the creature is almost without smell or taste. This, Dr. Ogle 
believes, explains the curious case of the pigs in Virginia ad- 
du y Mr. Darwin, white pigs being poisoned by a poisonous 
root which does not affect black pigs. Mr. Darwin imputed 
éscape; white 
Euphorbia candelabrum ; and white horses are said to suffer 
om poisonous food where colored ones escape. Now it 1s 
very improbable that a constitutional immunity from poisoning 
Y 8o many distinct plants should in the case of such widely 
smell and taste are dependent on the presence of a pigment 
Which is deficient in wholly white animals. The explanation has 
Owever, been carried a step further, by experiments showing 
that the absorption of odor by dead matter, such as clothing, is 
greatly affected by color, black being the most powerful ab- 
Sorbent, then blue, red, yellow, and lastly white. We have 
ere a physical cause for the sense-inferiority of totall white 
animals which may account for their rarity in nature. or lew, 
if any, wild animals are wholly white. The head, the face, or 
* Lorius, Eos (Trichoglosside), Eclectus (Palzornithide). 
t Microglossus, Calyptorhynchus, Turacen: 
ENnas. ie 
Medico-Chirurgical Transactions, vol. liii, (1870). 
2 
