406 THE CLASDULAR ORGANS. 



ments of the glands has been considered in the section on the Animal 

 Cell and in studying the leucocytes of the blood (pages 303 and 

 322). To recapitulate in brief, the cells contain small amounts of 

 allmmin, a very large proportion of nucleo-histon, besides lecithins, 

 fats, cholesterins, traces of glycogen, succinic acid, and larger amounts 

 of nucleinic bases, among which adenin predominates. 



In the spleen we also meet with uric acid, and, as in the liver, 

 with iron-containing nucleins and iron albuminates, which may be 

 isolated as there described. In addition, small amounts of inosit, 

 jecorin, and cerebrosides- may be encountered. Of special inter- 

 est is the fact, which has been established by Gulewitsch, th.it 

 arginin is a normal constituent of the spleen. All these bodies 

 have been described and require no further consideration at this 

 place. 



THE KIDNEYS. 



In addition to the common albuminoids which enter into the com- 

 position of the supporting tissue of the kidneys, we find the common 

 extractives, viz., nucleinic bases, uric acid, urea, leucin, inosit, gly- 

 cogen, fats, and at times taurin. All these substances, however, are 

 present in only small amounts. On one occasion, in the ox, cyst in 

 has also been encountered, but it is questionable whether this is a 

 constant constituent of the organs. Of albumins, Halliburton has 

 isolated a globulin and a nucleo-albumin, with coagulation-points of 

 52 C. and 63 C., respectively. In addition, a mucin-like body 

 has been found, which does not yield a reducing substance, however, 

 on boiling with mineral acids, and which is probably a nucleo- 

 albumin. It is notably found in the papillary portion of the kidneys, 

 while the other nucleo-albumin is principally met with in the cortical 

 portion. Serum-albumin is said to be absent. 



THE MAMMARY GLANDS. 



The chemical composition of the mammary glands has not been 

 studied in detail. We know, however, that the protoplasm of 

 the functionally active glands is rich in albumins, and it appears 

 that, as in the case of the pancreas, a very complex nucleo-gluco- 

 proteid is here also present, and is probably intimately concerned in 

 the formation of two of the most important constituents of the milk, 

 viz., the casein and lactose. It may be obtained in solution by first 

 washing the p:land thoroughly in water, so as to free it from milk ; 

 it is then extracted with a 0.5 pro mille solution of sodium hydrate 

 at ordinary temperatures. Such solutions also contain the common 

 albumins, and represent an exceedingly viscid, stringy fluid, from 

 which the proteid in question can be precipitated by acidifying care- 

 fully with dilute acetic acid. On boiling with dilute acids the sub- 

 stance is decomposed into albumin, phosphoric acid, and a reducing 

 substance of unknown composition. On digestion with gastric juice 

 it yields a paranuclein. 



