OF THE rabbit's TONGUE. 301 



that organs similar to those we have been discussing have been found 

 on the external skin of fresh water fish. "Regarded atfirst by Leydig 

 as tactile organs, they have since been proved by Schulze to be in 

 reality gustatory organs ; they have been found in the mouth, the 

 palate and on the lips of cyprinoid fishes, and traced from these parts 

 over the greater part of the external surface. The investigation of 

 this subject has not to my knowledge been pursued to any extent in 

 the direction of the invertebrata, and doubtless much of interest and 

 importance awaits the student who has the courage to tap that his- 

 tological spring. I cannot close this communication without ac- 

 knowledging how much I am indebted to the valuable and interest- 

 ing researches of Professor Englemann as published in Strieker's 

 " Human and Comparative Histology," and also my thanks are due 

 to Mr. J. W. Groves, who with his new freezing microtome has 

 cut some of my thinnest and most instructive sections. In con- 

 clusion, I would warmly urge and encourage all who really wish 

 to advance our knowledge by means of the microscope, to take 

 up the investigation of the marvellous structures which enter into 

 and help to make up the temple of the animal frame, and all other 

 studies will " pale their ineffectual fires" before that which I urge you 

 to adopt. Life is too short to spend in only testing the powers of our 

 instruments, but having once proved them capable of good work, 

 go onward and accomplish victoriously the conquests waiting at your 

 very feet, then your cabinets will be filled with the spoils of your 

 warfare, and your soul will be satisfied with the labours of your life. 



DESCRIPTION OF PLATE XXII. 



Fig. 1. — A diagrammatic section cut across the course of the gustatory 

 lamellae, showing — 



a. Gustatory bulbs. 

 h. Punctiform papilla. 



c. Connective tissue with nerves. 



d. Lingual glands. 



The muscular fibres of the tongue have been omitted for the sake 

 of clearness. 

 Fig. 2. — Isolated gustatory bulb. 

 Fig. 3. — Isolated investing cells. 

 Fig. 4. — Upper half of epithelial covering of gustatory bulbs ; a gustatory 



pore. 

 Fig. 5. — A gustatory bulb exposed in consequence of the detachment of 



upper half of epithelial covering. 



