Calcification. 219 



formed into a branched, rigid and corset-like enclosing structure. 

 In the dense membranes of the spinal cord, in dogs, calcareous in- 

 filtration gives rise to rigid thickenings which feel like splinters 

 of wood. Bursce and tendon sheaths in horses may become ex- 

 tensively calcified and ossified. The colloid matter often met in the 

 thyroid gland and sometimes involving the connective tissue as well 

 as the acini, may occasionally terminate in calcification of the organ 

 (stoa.e goitre, slniDia pctrifica}is,m dogs). The herbivora and also 

 hogs are with special freciuence subject to calcareous infiltration of 

 tuberculous caseated tissues. The yellow, cheesy foci produced 

 by coagulation necrosis are frequently full of sandy, gritty particles 

 and are very hard. In the end dead parasites and the connective 

 tissue capsules which are formed about such foreign bodies in the 

 parenchymatous organs, as echinococci and round worms in the 

 livers of horses, become so permeated with lime salts that they form 

 stony, bone-like or mortar-like, chalky masses. 



In women, dead foetuses long retained in the uterus or peritoneal 

 cavity may become so completely calcified as to be of stone-like hardness 

 {petrified foetus, lithopcrdion) ; in our dom.estic animals the dead embryos, 

 which are often found, usually remain more or less leathery, pliable and 

 merely mummified. [In the museum of the Medical Department of the 

 University of Pennsylvania there is a thoroughly calcified excellent example 

 of a lithopa^dion taken, after death, from the uterus of a mare, and pre- 

 sented to Dr. James of the above-named institution in 185 1 by -\Ir. Kearney 

 of Gloucester County, New Jersey.] 



Zschokke (Schicci::. Archil'. 1902) has descrilK-d a peculiar crystalline 

 deposit observed in the liver of a cow confined to the interstitial spaces 

 as white foci, scattered here and there. The abundant precipitate was 

 made up of rounded and rhombohedral crystals (about the size of white 

 blood corpuscles), the chemical nature of which was not precisely deter- 

 mined, although with the iodine-sulphuric acid test they showed some 

 relation to cholesterin. 



Solid u.norganized bodies which are formed in the secretions and 

 cavities of the body are called concretions. They are formed by 

 the precipitation of salts which have become insoluble ; their chemi- 

 cal composition depending upon the ingredients of the normal se- 

 cretions and its existing changes, and therefore not uniform. 

 Sometimes they contain organic matter mingled with the saline 

 constituents ; or they may be foreign bodies or exudates which have 

 become encrusted with salts. The fundamental conditions for the 

 formation of these bodies include the following: 



I. Supersafnnttion of the saline solution (Klimmer) and dim- 

 inution of the medium of solution. Just as the crystalline salt 



