THE NERVOUS SYSTEM. 



367 



Cystin (Fig. 132) is an occasional constituent of urine. It 

 resembles taurin in containing a large quantity of sulphur- 

 more than 25 per cent. It does not exist in healthy urine. 



Another common morbid qonstituent of the urine is oxalic 

 acid, which is frequently deposited in combination with lime 



FIG. 181. 



FIG. 132. 



Crystals of oxalate of lime. 



Crystals of cystin. 



(Fig. 131) as a urinary sediment. Like cystin, but much 

 more commonly, it is the chief constituent of certain calculi. 

 A small quantity of gas is naturally present in the urine 

 in a state of solution. It consists chiefly of carbonic acid and 

 nitrogen. 



CHAPTER XVI. 



THE NERVOUS SYSTEM. 



THE nervous system consists of two portions or systems, the 

 cerebro-spinal and the sympathetic or ganglionic, each of which 

 (though they have many things in common) possesses certain 

 peculiarities in structure, mode of action, and range of influ- 

 ence. 



The cerebro-spinal system includes the brain and spinal 

 cord, with the nerves proceeding from them, and the several 

 ganglia seated upon these nerves, or forming part of the sub- 

 stance of the brain. It was denominated by Bichat the ner- 

 vous system of animal life; and includes all the nervous organs 

 in and through which are performed the several functions 



