248 MACERATION CORROSION 



are gastric juice (or pepsin) and pancreatic juice (pancreatin or 

 trypsin). 



Pepsin is best employed in acidified solution, pancreatin in 

 alkaline. 



The most favourable temperature for digestion is about 40° C. 



Pepsin digests albuminoids, collagen substance and mucin 

 more or less readily, elastin more slowly. Nuclein is either not 

 dissolved or very slowly. Keratin, neurokeratin, chitin, fat and 

 carbohydrates are not attacked. 



Pancreatin (trypsin) digests albuminoids, nuclein, mucin, and 

 elastic tissue ; whilst collagen substance, reticular tissue, chitin, 

 horny substances, fat and carbohydrates are not attacked. 



Tissues for digestion should be fresh, or fixed with alcohol, not 

 with chromic acid or other salts of the heavy metals. 



582. Pepsin (Beale's, Archives of Medicine, i, 1858, pp. 296 — 

 316). The mucus expressed from the stomach glands of the pig 

 is rapidly dried on glass plates, powdered, and kept in stoppered 

 bottles. Eight-tenths of a grain will dissolve 100 gr. of coagulated 

 white of egg. 



To prepare the digestion lluid, the powder is dissolved in dis- 

 tilled water, and the solution filtered. Or the powder may be 

 dissolved in glycerin. The tissues to be digested may be kept 

 for some hours in the liquid at a temperature of 100° F. (37° C). 



Brucke's (from Carnoy's Biologic cellulaire, p. 94). 



Glycerinated extract of pig's stomach . 1 volume. 

 0-2 per cent, solution of HCl . . 3 volumes. 



Thymol, a few crystals. 



BiCKFALVi's {Centralh. med. Wiss., 1883, p. 838). One grm. 

 of dried stomachal mucosa is mixed with 20 c.c. of 0-5 per cent, 

 hydrochloric acid, and put into an incubator for tliree or four 

 hours, then filtered. Macerate for not more than half an hour 

 to an hour. 



KusKow's {Arch. mik. Anat., xxx, p. 32). One part of pepsin 

 dissolved in 200 parts of 3 per cent, solution of oxalic acid. The 

 solution should be freshly prepared, and the objects (sections of 

 hardened Ligamentum Nuchae) remain in it at the ordinary 

 temperature for ten to forty minutes. 



583. Pancreatin. Schiefferdecker's (Zeit. wiss. Mik., iii, 

 1886, p. 483). A saturated solution of the " Pankreatinum 

 siccum," prepared by Dr. Witte, Rostock, is made in distilled 

 water, cold, and filtered. Pieces of tissue (epidermis) are 

 macerated in it for three to four hours at about body temperature. 



KiJHNE's (Unters. a. d. Phys. Inst. Univ. Heidelberg, i, 2, 1877, p. 219). 

 — Very complicated. 



See also Gedoklst, La Cellule, iii, 1887, p. 117, and v, 1889, p. 126 ; 

 Maas, Festschr. Kupffer, 1899, p. 211, and Hoehl, Arch. Anat. Phys., 



