Harrison R. Hunt

“ The large number of wild Norway rats that can usually be caught in human communities, together with the ease with which albinos can now be secured from dealers, makes the Norway rat a convenient form for laboratory study by large classes. ”

“ When well fed it is said that a female Norway rat can give birth to from sixty to a hundred young a year. It is more of a burrower than the black or roof rat, and is the common form found about bams, houses, warehouses, etc., in the United States. ”

“ Observe and determine the numbers of the footpads, or plantar tubercles, on the ventral surfaces of the fore and hind feet. In feeding on a morsel of food, rats are said to assume a sitting posture, and to hold the food between the fore paws while gnawing at it, like a squirrel. ”

“ Mus rattus rattus (the black, or house rat) is the rat of the Middle Ages in Europe. It probably reached that continent some six hundred years before the Norway rat arrived. The black rat preceded the Norway rat in North America, and occurs still in scattered localities in the northern United States. Its diagnostic characteristics are: the ears when laid forward extend at least to the middle of the eye; the tail is longer than the head and body ”

“ Note the exposed, sharp, chisel-like, canine teeth which the rat uses in gnawing hard objects. The long hairs, or vibrissae, which project laterally from the animal's snout doubtless serve as feelers. Rats in the daytime appear to have poor vision while in the open, for their movements are then uncertain or slow. ”

“ The enamel is restricted to the front of the incisor, so that in gnawing the softer dentine is worn away at the tip faster than the enamel, thus keeping the tooth sharp. There are no canine teeth. Rodents are mostly herbivorous in diet, are usually small, and have clawed digits. ”

“ It is claimed that the plague, or "black death," killed 25,000,000 people in Europe during the fourteenth century, and that plague has caused the death of nearly 9,000,000 persons in India alone since 1896. ”