42 GENERAL HISTOLOGY. 



tissue are most fitted for fatty deposits, the lungs for salts of 

 lime, the kidneys, liver, spleen, etc., for amyloid matter. 



1. Albuminous infiltration, or cloudy swelling, is a deposit 

 of molecular albumen in the tissues. Virchow regarded it as 

 a nutritive change, on account of which the cells take up an 

 abnormal quantity of pabulum. In the liver and kidneys it is 

 often connected with fatty degeneration and fibrinous exuda- 

 tion. 



2. Serous infiltration is a deposit in the tissues of serous or 

 sero-mucous substance, producing oedema, as in herpes, eczema, 

 or in blisters from vesication. 



3. Pigmentary infiltration is derived from the coloring mat- 

 ter of red blood corpuscles. Pigments are usually eliminated 

 by the kidneys or liver, but are sometimes deposited elsewhere, 

 as normally in the choroicl coat of the eye and the rete mal- 

 pighii of the skin. Some pathological cases may be due to 

 local blood stasis or extravasation, and others to wandering 

 leucocytes, which take up particles of pigmentary or foreign 

 matter, and transfer them to other places. Thus dark spots 

 in the lungs maybe due to soot particles from the atmosphere 

 taken up by leucocytes of the trachea and bronchi, which are 

 either expectorated or make their way to the lungs. In coal 

 miners such deposits of carbon may render the lungs quite 

 black. Workers in iron dust may have lungs infiltrated by 

 oxide of iron, and a deposit of fine sand in the lungs of stone- 

 cutters may set up inflammation. As the color of bile is from 

 the blood, jaundice may be regarded as an infiltration of pig- 

 ment in the blood. 



4. Fatty infiltration must be distinguished from fatty degen- 

 eration. The first is derived from the blood, and the latter is 

 a metamorphosis of the tissue. In fatty infiltration the fat 

 occurs in the cells as distinct drops of oil, which may be ab- 

 sorbed and deposited elsewhere. In muscular fibers the oily 

 drops are seen between the fasciculi, and not in the fibers 

 themselves, as in fatty degeneration. The "fatty liver" is due 

 to infiltration. The ingestion of fats is followed by its tem- 

 porary accumulation in the portal blood and deposition in the 

 portal zone of the liver cells. In advanced cases of disease, 



