86 ATROPHY, DEGENERATION, PIGMENTATION, AND NECROSIS. 



cell. In this way, and by the atrophy of intercellular substance which 

 its accumulation causes, cysts may be formed containing colloid material 

 and cell detritus. Colloid degeneration is of most frequent occurrence in 

 the thyroid gland. "iTniaterial resembling, if not identical with, colloid 

 is occasionally seen in the form of homogeneous globules in the tubules of 

 kidneys which are the seat of other lesions, in the hypophysis, and in 

 various tumors. 



TECHNIQUE. Tissues should be hardened in formalin, or Orth's fluid, and stained 

 with picro-acid fuchsin. 



HYALINE DEGENERATION. 



This is the transformation of tissues into a transparent, glassy sub- 

 stance, much resembling amyloid in its morphological characters (Fig. 

 24) ; but it does not give the micro-chemical reactions of amyloid, and 



appears under different condi- 



/>,. 7 .-"/ <F % ' ~ *r*\ i V c x . < V-"p"-\ tions. Hyaline substance is re- 

 Jj "' ' ' "'V, **'+,"'& \. * sistant to the action of acids, and 

 ' / ' V, ' ,, f : l( ,i' ; /, ' stains readily with acid fuchsin 

 iV ' ^ .-'.'.-. -f . >: /' *' and eosin. It occurs especially 



/"'/'/''' "^ /,,'.--, , '' in the Avails of the smaller blood- 

 vessels in various parts of the 

 f ' body, in voluntary muscle fibres, 

 .'/ ',. and is said sometimes to in- 

 , -<jV volve interstitial tissue. It has 

 been described as occurring in 



SMALL BLOOD-VESSELS. 



From a Sarcoma. ovaries; in the tubules of th:> 



kidney, in the walls of aneur- 



isms, in muscle fibres, in the lesions of diphtheria, tuberculosis, and 

 syphilis, in the hyaloid membrane and vessels of the eye, and elsewhere. 

 It is believed by some observers that fibrin, blood plates, and leucocytes 

 may undergo hyaline degeneration, and in the form of the so-called hyaline 

 thrombi this substance may block the capillaries in many infectious dis- 

 eases typhoid fever, pneumonia, diphtheria, pyaemia, etc. and under 

 other conditions (see p. 75). Hyaline degeneration seems to be, in some 

 ways, allied to coagulation necrosis, but its exact significance and rela- 

 tions to other forms of degeneration, and the conditions of its occurrence, 

 are not yet known. There are probably various substances, occurring 

 under many different conditions, which we now call hyalin and whose 

 relationship to each other and to amyloid, mucoid, and colloid material 

 is little understood. 1 



TECHNIQUE. Hardening in alcohol, Orth's fluid, or formalin. Staining by picro 

 acid fuchsin, or by htvinatoxylin and eosin. 



1 Consult for bibliography of studies on hyaline degeneration Lwbarick and Ostertag's 

 "Ergebnisse dcr allg. path. Morphologic und Physiologic," etc , Jahrg i., Abth. i., 

 1895, p. 201. 



