168 PHYSIOLOGICAL CHEMISTRY. 



contain cells rich in mucin but poor in albumin. A cell rich in 

 albumin may also occur in the submaxillary and sublingual glands 

 between the mucus-cells and the membrana propria, which in a 

 few cases akes the form of a half-moon (lunula, according to 

 GIANUZZI), and in other cases the cells rich in mucin are sur- 

 rounded as by a ring, and sometimes certain alveoli may be com 

 pletely filled. By continuous secretion the mucin-cells seem to 

 give up all their mucin (EwALD, STOHR), so that only albumin-cells 

 are to be seen (HEIDEJSTHAIN). During rest the mucin-cells are 

 re-formed. According to the analyses of OIDTMAN, the salivary 

 glands of a dog contain 790 p. m. water, 200 p. m. organic and 10 

 p. m. inorganic solids. Among the solids, in addition to albumin, 

 we find, nucleoalbumin and mucin, diastatic enzyme, in certain 

 animals nuclein, extractive bodies, leucin, traces of xanthin bodies, 

 and mineral substances. 



The saliva is a mixture of the secretion of the above-mentioned 

 groups of glands; therefore it is proper that we first study each of 

 the different secretions by itself, and then the mixed saliva. 



The submaxillary saliva in man may be easily collected by 

 introducing a canula into the Wharton's duct. 



The submaxillary saliva has not always the same composition 

 or properties; these depend essentially upon the conditions under 

 which the secretion takes place. That is to say, the secretion is 

 partly dependent on the cerebral, partly on the sympathetic, 

 nervous system. In consequence of this dependence the two dis- 

 tinct varieties of submaxillary secretion are distinguished as cliorda- 

 and sympathetic saliva. A third kind of saliva, the so-called para- 

 lytic saliva, is secreted after poisoning with curara or after the 

 severing of the glandular nerves. 



The difference between chordal and sympathetic saliva (in dogs) 

 consists chiefly in their quantitative constitution, namely, the less 

 abundant sympathetic saliva is more viscous and richer in solids, 

 especially in mucin, than the more abundant chordal saliva. The 

 specific gravity of the chordal saliva of the dog is 1.0039-1.0046 and 

 contains from 12 to 14 p. m. solids (ECKHARD). The sympathetic 

 has a specific gravity of 1.0075-1.018, with 16-28 p. m. solids. The 

 gases of the chordal saliva have been investigated by PFLUGER. He 

 found 0.5-0.8$ oxygen, 0.9-1$ nitrogen, and 64.73-85.13$ carbon 



