52 



CALCIFICATION. 



owing to the absence of lymphatics, stand in some sort of causal 

 relation to the process of calcification. Should this view be 

 correct, we might conceive the precipitation of the earthy salts 

 to occur in some way like this : the free carbonic acid, to which 

 their solubility is due, in consequence of its great diffusive power, 

 forsakes the stagnant nutrient fluid, and escapes from the organism 

 by other channels ; while the calcareous salts, rendered insoluble 

 by its removal, are forthwith deposited in a solid form. 



§ 53. Passing next to pathological calcification, we find 

 it occurring chiefly as a secondary phenomenon, as a consequence 



Fig. 17. 





Calcification of cartilage. Transverse section through the 

 zone of proliferation in the epiphysal cartilage of a rachitic 

 subject, Tu" 



of inflammation and morbid growth. The earthy matter is 

 deposited either in the newly- formed tissues themselves, or in the 

 residual parts of the diseased organ, which are surrounded and 

 permeated by the products of inflammation and morbid growth. 

 To what extent we may be justified in assuming a disturbance 

 in the circulation of nutrient juices as the efficient cause of the 

 precipitation of the earthy salts in each single case, we shall see 

 when we consider them individually. Calcification may occur 

 in various tissues ; in the connective tissues, in vessels, in cel- 

 lular and glandular tissues, in muscle, both striped and un- 

 striped, but oftenest in cartilage, the pathological coinciding 

 here with the physiological order. The cartilages of the larynx 

 and trachea are often found calcified, as a result of chronic 

 catarrh of the respiratory mucous membrane ; the intervertebral 

 substances, in consequence of chronic suppurative caries of the 

 vertebrae ; the costal cartilages of old people are often affected 



