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leg was amputated, and the medulla of the tibia found to be 
of a grey colour below, and greyish-red in the upper part, 
while the microscope detected a large number of fat-cells. In 
starved rabbits the corresponding structure was found of a 
dark red colour, and highly vascular. The microscope 
showed enormous dilatation of the vessels ; the veins in some 
parts touching one another, and leaving hardly any space for 
the proper medullary tissue. Where there was any interval, 
it was found occupied by amorphous matter, or else by nothing 
but medullary cells. 
Development of Fatty Tissue. — Flemming, in ‘ Max 
Schultze’s Archiv,’ vol. vii, p. 32, in a paper entitled “‘ Ueber 
Bildung und Riickbildung der Fettzelle im Bindegewebe,” 
discusses the formation of adipose tissue, its relation to con- 
nective tissue, and its retrogression into the condition of the 
latter. His observations were made on embryoes and newly 
born animals, and also on animals artificially fattened, in 
order to make sure that the fatty tissue should be in the 
condition of increase; also on animals in a state of progres- 
Sive emaciation. He is in agreement with most of the 
physiological and pathological observers on the point that 
fatty tissue is nothing but a modified connective tissue. The 
only observer who had previously investigated the subject by 
artificial fattening was Czajewicz, with whom Flemming does 
not always agree. Flemming finds that the development of 
fat is always dependent on vessels. The first deposit of fat 
takes place in the tunica adventitia of the blood-vessels, so 
that adipose tissue might in fact be called a loosely spread 
adventitious coat of the vessels. Moreover, the fat does not 
accumulate round newly-formed outgrowths of vessels, but 
rather round those which are completely formed and com- 
paratively thick. The mesentery, which has been studied by 
previous observers, was found to be an unsuitable object. 
The subcutaneous tissue of mammalia was preferred. The 
advantages of observing mammalia are, that by artificial 
fattening an unquestionable production of fat can be secured. 
Rabbits, on account of their numerous parasitic diseases, are 
unsuitable. Guinea pigs and puppies are better. Young 
mammalia, still sucking, or shortly before birth, show the 
same fat-generating process as artificially fattened animals. 
The production of fat takes place only in isolated foci, round 
certain vessels of the fatty lobule, while other quite similar 
vessels show nothing of the kind. The fat does not appear 
at first, as observed by Czajewicz, in the periphery of the 
lobules, nor is it contained, as has been asserted by other 
observers, in special, smaller cells. A certain quantity is 
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