66 



IMMEDIATE PRINCIPLES OF THE TISSUES. 



if the aerating process is in any way disturbed, and is common in 

 pulmonary emphysema and chronic bronchial catarrh, and in con- 

 valescence from severe diseases as typhus. It is always accompa- 

 nied in the urine by lactic acid. 



The mulberry calculus (Figs. 32 and 33) consists mostly of the 

 oxalate of lime, and the latter enters in small quantity into almost 



Fig. 32. 



Fig. 33. 



Oxalate of lime (mulberry) calculus. 



Section of mulberry calculus. 



Fig. 34. 



all the varieties of calculi. It often forms alternate layers with uric 



acid (Fig. 34), a fact disproving the notion 

 of the "uric acid diathesis." 



In some cases of gout, the oxalate of 

 lime exists in the blood. (Grarrod.) 



Origin. Oxalic acid (C 2 3 ) in the organ- 

 ism is normally converted into carbonic 

 acid by oxidation C 2 3 becoming C 2 4 , 

 or 2(C0 2 ). Any cause preventing this ox- 

 idation, therefore, causes an accumulation 



Alternating calculus of oxaiate of f u ^ which, combining with lime, 



lime and uric acid. 



forms the salt under consideration. Oxa- 

 late of lime, therefore, proceeds 1. From the oxalate in vegetable 

 food. 2. It accumulates if there be an excess of carbonic acid gas 

 in the organism (as from beer, &c.). 3. Impeded aeration, producing 

 diminished oxidation, may increase it; and hence debility of the 

 nervous system may do so indirectly, by diminishing the respira- 

 tory movements. 4. Finally, oxalic acid may be produced by the 

 oxidation of uric acid and several other substances in the organism ; 

 and hence diminished oxidation may produce more uric acid, and 

 less oxalate of lime, so far as this source of the latter is concerned, 



