From my early youth I have had the strongest desire to understand or explain whatever I observed. ... To group all facts under some general laws.
Charles DarwinThe lower animals, like man, manifestly feel pleasure and pain, happiness and misery. Happiness is never better exhibited than by young animals, such as puppies, kittens, lambs, &c., when playing together, like our own children.
Charles DarwinThe young blush much more freely than the old but not during infancy, which is remarkable, as we know that infants at a very early age redden from passion.
Charles DarwinThe number of humble-bees in any district depends in a great degree on the number of field-mice, which destroy their combs and nests; and Mr. H. Newman, who has long attended to the habits of humble-bees, ... says "Near villages and small towns I have found the nests of humble-bees more numerous than elsewhere, which I attribute to the number of cats that destroy the mice." Hence it is quite credible that the presence of a feline animal in large numbers in a district might determine, through the intervention first of mice and then of bees, the frequency of certain flowers in that district!
Charles Darwin