oison of any of the exanthemata, from those witnessed in the
meat or promiscuously dieted child. We can also appreciate that
different individuals have different susceptibilities to disease, as
well as we understand that the same degree is not always in an unvarying
point of resistance or susceptibility in the same individual. The
investigation and study of these conditions teach us, however, that
there is a cause, or that there are causes that induce and modify this
susceptibility. But there are conditions that are as yet beyond our
comprehension. Take, for instance, two animals, both vertebrates,
mammals, and dwelling together, eating the same food, and even having a
mutual understanding or sympathy of mind and affections, having a like
circulation, a like brain and nervous system, it would naturally be
supposed that these two would exhibit a like susceptibility to the
actions of narcotic poisons; but when we are told that one dog has
taken 21 grains of atropia with impunity we are staggered. Atropia may
not affect rabbits (as it does not), but the rabbit does not approach
man in the same close relationship as the dog. Richardson administered
to a healthy young cat 7 drachms of Battley's solution of opium, then 10
grains of morphia, and a little later 20 grains more of morphia without
rendering the cat unconscious. The same experimenter gave to a pigeon
21, 30, and 40, then 50 grains of powdered opium on succeeding days with
no bad effect. S. Weir Mitchell gave to three pigeons, respectively, 272
drops of black drop, 21 grains of powdered opium, and 3 grains of
morphia without any effect.[72] On the other hand, horses show a like
susceptibility to man to the action of drugs. In the island of Ceylon, a
sloth can take 10 grains of strychnia with safety,--chickens presenting
a like immunity to the poisonous effects of this alkaloid. While the dog
offers such a contrast to the action of drugs as compared to man, he is
as subject to goitre, and they have been seen in a true state of
cretinism.[73]

An Apache, or Colorado Indian, will prefer a dessert of decomposed
gophers to one composed of the best canned peaches or Bartlett pears; he
will devour the mass without any resulting evil, while a German--after
many generations of training on all forms of sausages in every degree of
age and ripeness, and on every form of cheese, from the refreshing
cottage cheese from curdled milk and the delicious cream cheese, down
through to