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which increase, become confluent, and become intensely yellow in color. The 
liver increases enormously in size, and finally looks marbled, with sp,ots of 
yellow and brown. In the]darker parts of the liver there are usually still fresh 
grey little knots to be seen. 
In the dissection of a guinea pig tuberculous in a high degree, beside the 
lungs permeated with little grey knots, the spleen, immensely enlarged and 
marbled with light grey and blackish-grey, and the liver also decidedely enlarged 
and marbled in brown and yellow, attract the eye, and it gives a total which can 
be mistaken for no other disease occurring in these animals. By the micro¬ 
scopic investigation of a spleen or liver so changed it is shown that in the 
light colored parts no nucleus coloring occurs ; the cells have died and indeed 
a sort of “ coagulation-necrosis ” is present. A large part of the organ is dead, 
but no further dissolution occurs, the organ keeps its form and has only 
changed its color. In these dead masses usually only scattered bacilli are to 
be found. Only in single cases I have seen a peculiar increase and arrange¬ 
ment of the bacilli in the necrotic livertissue, of which I will speak later. The 
bacilli occur more or less numerously on the border of the necrotic parts, and 
are then frequently enclosed by giant cells. 
In the kidneys of guinea pigs 1 have never observed tubercles visible to the 
naked eye. 
In rabbits the spleen and liver also appear enlarged, though in a far less degree 
than in guinea pigs. In this animal the tubercles always remain small and in¬ 
significant in the organs named, and there are never such changes as were described 
in the case of guinea pigs. On the contrary, the kidneys are almost always sup¬ 
plied with a number of whitish knots, which grow to the size of peas. In these 
knots the tuberculous bacilli are usually found in abundance, and mostly arranged 
in nests. Sometimes also I have found urethrae which were filled with bacilli. 
8.—Artificially generated Tuberculosis in Animals. 
Artificially generated tuberculosis conducts itself in general just like that 
which arises spontaneously. It takes also the form characteristic of every special 
species of animals, and in fowls, for example, leads to the development of com¬ 
pact, knotty tumors on the intestines and the liver; in rabbits to the formation of 
small gray tubercles with yellowish centre in lungs and spleen, and larger whitish 
knots in the kidneys; and in guinea pigs causes the considerable enlargement of 
the spleen and liver, together with the peculiar gray or yellow marbled coloring 
of these organs. 
Of course the various sorts of infection condition certain differences in the 
course of the tuberculosis in the form of the pathological changes. It is of the 
greatest significance whether the infection was brought about with very few bacilli 
or with greater numbers of them. The distinction conditioned upon this may be 
studied most simply in the eye of the rabbit. Namely, if as few bacilli as possible 
be put into the anterior eye-chamber there arise first separate little gray knots, 
genuine miliary tubercles, which become yellowish in the centre. Their number 
increases gradually, they finally become confluent and not until after a consider¬ 
able time do they lead to the general caseous degeneration and destruction of the 
eye as well as to the appearance of tubercles in other organs. When, on the con- 
