306 



PHYSIOLOGY OP THE DOMESTIC ANIMALS. 



and seem to be cells in a state of active growth and multiplication. 

 When a similar section is prepared from a salivary gland which has been 

 exhausted by prolonged stimulation of the chorda tympani nerve, the 

 muciparous cells will, as a rule, have largely disappeared. All the cells 

 are now small in size and all stain deeply (Figs. 126, 127, and 128). It 

 ■would appear from this that in such a gland stimulation of the chorda 

 nerve leads to a discharge of mucin, or to a total breaking down of the 



Fig. 126.— Orbital Gland of the Dog in the Resting Condition. (Heidenhain.) 



Fig. 127.— Orbital Gland of Dog-Commence- Fig. 128.-Orbital Gl and of Dog- 



!«rS„T G , AC ™"' A ™ K Highest Degree :of Change ix 



Ladvovsry. (Heidenhain.) Activity, after Ladvovsky. 



(Heidenhain. ) 



entire cell, whose place is then taken by the new, rapidly growing, half- 

 moon cells. Both statements are probably correct. 



It is thus seen that the secretion is the result of the activity of the 

 protoplasm of the secretin- cell. During rest the mucous gland manu- 

 factures mucin at the expense of its protoplasm. When such a gland 

 secretes, the mucin is discharged and new protoplasmic cells are rapidly 



