THE JOURNAL 



OF THI^ 



utlutt lltirr0st0pintl <&htfr. 



On the Salivary Glands of the Cockroach. 



By T. Charters White, M.K.C.S., F.R.M.S., &o. 



Read Sept. 25, 1874. 



As my communication this evening must be regai'ded more in 

 the light of an introduction to an interesting object than in that of 

 an elaborated paper, I shall not enter to any great extent 

 into the structure and functions of the various glands met with in 

 the animal frame, but it is necessary to the proper understanding 

 of the salivary glands of the cockroach which I exhibit to-night 

 that I should, for the advantage of those present who may have no 

 technical knowledge of the subject, explain briefly the functions 

 destined to be performed by a gland, and the types upon which the 

 various glands are constructed. The office of a gland is the 

 elimination of certain materials from the blood, which are either 

 stored up for future use in the animal economy, or are cast out as 

 effete and deleterious to the system ; we may instance the gastric, 

 juice and the saliva, as illustrating the first, and the urine and 

 < sweat as examples of the second. That this process may be fully 

 and perfectly carried out, the blood must be brought into close 

 proximity with the agents by which this eliminating process is 

 effected, and an examination of the gland will show the elements 

 whereby this change is produced. We may realise from Dr. 

 Sharpey's description better than from any words of mine, the 

 structural elements concerned in secretion, and therefore with your 

 permission I will quote them. He says — " In the structural adap- 



YOL. III. b 



