64 FATTY INFILTRATION. 



only in very rare cases, is the biliary pigment deposited in a solid 

 form ; the pigmentary imbibition does not become a pigmentary 

 infiltration. The latter, as has been already stated, occm's only 

 in the liver and the bile-ducts. VircJioiv detected crystalline 

 deposits of bilifulvin in the epithelium of the gall-bladder ; 

 granular pigment, of a yellow, brown, and especially of a black 

 colour, is met with in the hepatic cells, not only in cases where 

 the escape of the bile is hindered, but also in cases of obstruc- 

 tion to the return of blood from the hepatic veins. Here too 

 we may have a coincident atrophy of the pigmented cells ; but 

 we must beware of regarding the pigmentary infiltration as the 

 cause of the atrophy. This will become clear hereafter from the 

 history of the pigmented nutmeg-liver, cirrhosis, &c. 



D. Fatty Infiltration, 



§ 61. The last member of the present series, and of the 

 passiv^e tissue-changes in general, is fatty infilteation. This 

 must not be confounded with that fatty metamorphosis which has 

 already been treated among the conditions of involution. There 

 the oil-Mobules were but the forerunners of imminent dissolu- 

 tion; here they are, at worst, but a superfluous constituent 

 of the cell ; there tliey appeared as a product of the decom- 

 position of the body of the cell ; here they are brought to the 

 cell from without, and retained in its protoplasm. Hence 

 too, the anatomical appearances presented by fatty infiltration 

 differ wholly from those due to fatty metamorphosis. They agree 

 in this alone — that minute oil-globules make their appearance 

 Fig ^3 ^^ ^^^ interior of the protoplasm. While, 



however, in the case of fatty metamorphosis 

 these oil-globules continue to increase in 

 number, without ever uniting to form larger 

 :v^ drops, fatty infiltration mimics the develop- 

 Wm i^ei^t of real fat-cells (figs. 23 and 24). We 

 rarely see more than two or three separate 

 oil-globules in any one cell, and even these 

 hasten — if the phrase may be allowed — to 

 Liver-cells, mfil- ^^^^ tof^ether, so as to form a sino^le laro^e 

 trated with oil, mi ^ • ^ 



^J^ drop. ihe protoplasm, together with the 



