48 CALCIFICATION. 



length of time outside the current of the blood, became suscep- 

 tible of reacting to iodine ; now it appears that other albuminates 

 and albuminoid matters are capable of undergoing ar similar 

 change. The laminated concretions which are always present 

 in the follicles of the prostate gland of adults, exemplify the 

 possibility of an albuminous body being deposited in a solid 

 state from the secretion (mucous or colloid ?) of a gland, round 

 isolated cells, or groups of cells, and of its subsequently, though 

 not invariably, becoming susceptible of coloration by iodine, the 

 colour inclining usually rather to blue or violet than to red. 



By the concentric addition of similar matter these bodies may 

 reach a considerable size ; two or more may become invested by 

 a common capsule, in which case they may be recognised by the 

 naked eye, and their behaviour with iodine tested. 



The concentrically laminated cor- 

 puscles which are normally present in 



the ependyma of the cerebral ventricles, 

 and which occur in enormous numbers 

 in the so-called grey atrophy of nerve 

 tissue, have given rise to much discus- 

 Laminated concretions of ^ion ; their significance is purely local, 

 amyloid matter from the It is still undecided whether they are to 

 efferent ducts of the i i j n • r»ii j. j -xi 



prostate ^^ regarded as ceils nihltrated wath amy- 



loid matter, or as concretions ; their 

 remarkable uniformity of size, and their not Avholly irregular 

 distribution in the ventricular ependyma, are more in favour of 

 the former than the latter supposition. 



^Vith iodine they assume a pale blue tint, which passes into 

 violet on the addition of sulphuric acid. 



B. Calcijlcation. 

 Calcification plays a less important part in pathology than 

 amyloid degeneration. It denotes the infiltration of tissues with 

 calcic phosphate and carbonate in a solid form. The most gigantic 

 physiological prototype of this process — one, however, which 

 exhibits many peculiar features — is the deposition of calcareous 

 salts in the matrix of bone. On the other hand, it must be care- 

 fully distinguished from all crystalline deposits from the secre- 

 tions, as e.g. those occurring as sediments and incrustations in 

 the urinary passages. 



