414 RETROGRESSIVE CHANGES 



from the food, for he found lipeuiia oul}' in diabetics receiving fat in 

 their food, and under fasting an existing lipemia disappears. Choles- 

 terol increases parallel Avith the fat, while lecithin is relatively little 

 increased. In severe diabetes without lipemia the lipins are ail much 

 increased in the plasma, but with the relative proportions about as in 

 normal individuals, although with a tendency for the fats to accumu- 

 late in excess. The facts that fat oxidation depends upon carbohy- 

 drate oxidation, and also that in diabetics excessive fat feeding is 

 usual, are probably significant in the causation of diabetic lipemia. 



PATHOLOGICAL OCCURRENCE OF FATTY ACIDS 



Fatty acids occasionally occur free in pathological processes. The 

 l)est example of this is fat necrosis {q. v.), where cr3-stals of fatty 

 acids appear in the necrotic fat-cells, arising through splitting of fat, 

 and later becoming combined with calcium from the blood. Similar 

 crystals, consisting of a mixture of palmitic and stearic acids, fre- 

 iiuently called margarin or margaric acid crystals, may be found in 

 decomposed pus, in sputum from bronchiectatic cavities and from 

 gangrene of the lungs, in gangrenous tissue, and in atheromatous 

 areas. According to Schwartz and Kayser,^^ the free fatty acids, at 

 least in pulmonary gangrene, arise from lipolysis by bacterial action 

 rather than by the lipase of the tissues. Eichhorst found crystals of 

 fatty acids in the neighborhood of acute patches of sclerosis in the 

 central nervous system in multiple sclerosis, and McCarthy ^^ found 

 them in a spinal cord undergoing secondary degeneration from com- 

 pression. Whipple ^° describes a case with deposits of fatty acids and 

 neutral fat in the w^all of the intestine and the mesenteric glands, 

 while soaps and fatty acids are said to be present in excess in chronic 

 appendicitis."** Soaps and fatty acids, especially oleic acid and oleates, 

 are highly toxic, and their profound hemolytic power has been 

 thought of importance in pathological conditions, especially bothrio- 

 cephalus anemia."^ (See Hemolysins, Chap, viii.) The fatal dose of 

 sodium oleate for rabbits is 0.15 gm. per kilo (Leathes), The salts 

 of higher fatty acids above capric are hemolytic, while those from 

 caproic down are not, nonoic acid salts being the turning point 

 (Shimazono).''- The toxicity of soaps may be related to their marked 

 power to inhibit proteolytic enzymes.'^-'^ 



The fatty acids may be stained green by copper acetate, according 

 to Benda's method, and if then treated with hematoxylin, they turn 

 black."^ With Nile blue sulphate they stain blue, forming a blue 



57Zeit. klin. ^Mcd., 1905 (56), 111. 



58 Univ. of PtTin. Med. 15ull., 190:? (10), 141. 



50 Bull, .lohiis Hopkins Ilosp., 1!I07 (18), l^S'l. 



8'> .Anthony, .lour. Mod. Itos., 1911 (20), .S5!). 



ci Faust, Suppl. V,d.. ScliniicdclxTfi's Arch., lOOS, p. 171. 



•••2 Z. Inimunitiit., Kef., 1!)11 (4), (i.")6. 



"sa.Joblinp and Petersen, Jour. K.\p. Mod., 1014 (10), 251. 



03 Fischler, Cent. f. Path., 1004 (15), 013. 



