392 



Mr. G. F. Dowdeswell on the Connective 



ject have been warmly disputed. On tlie one hand the pathological his- 

 tologists of the Yienua School have maintained, on the basis of much 

 laborious work done bv Prof. Strieker and his pupils, the preyiously 

 received belief as to the textural origin of those young cells the presence 

 of which is the most essential characteristic of inflammation. On the 

 other hand Cohnheim, supported by Axel Key and many others, has 

 strengthened his view of the case by extending the research in new 

 directions. 



As regards the tongue of the frog, Prof. Strieker has published obser- 

 vations in which, following Cohnheim's own method, he arrived at oppo- 

 site conclusions. 



I have thought it desirable to publish the observations here recorded, 

 because the methods now adopted appear preferable to any previously 

 employed, the tongue of the toad being much better adapted for the study 

 of the tissues than that of the frog. 



The organ, when protruded, extends nearly an inch out of the mouth ; 

 and in this state exhibits near the mouth the form of a flattened cylinder, 

 of which the cross section is oval. Towards its extremity it becomes 

 flattened, and exhibits a tendency to bifurcation, ending in two short 

 tips, often called cornua. Of its two principal surfaces, of which one is 

 beset with papilla, the other smooth, the former (supposing the animal 

 to be in the supine position) is undermost. But when the organ is re- 

 tracted, and^ occupies its usual position in the mouth, it is bent back 

 in such a way that the papillated surface looks towards the palate. 



The arrangement and anatomical relations of the structures which con- 

 stitute the substance of the tongue may be most readily understood by 

 the examination of transverse sections. In any vertical section of a pro- 

 perly hardened tongue across the thicker part of the organ it is seen that 

 immediately underneath the mucous membrane of the smooth surface 

 there is a large cavity, which, from its liniug of flat cells, the ana- 

 tomist at once recognizes as a lymph- sac. The floor of this lymph- 

 sac is formed towards the middle line by a mass of musctilar fibres, of 

 which the direction is longitudinal, and from which the liquid contents 

 are only separated by the cellular lining. The under surface of the 

 muscular mass is also covered bv cells which form the lining of a second 

 lymphatic cavity, which is in a similar relation to the papillated mucous 

 membrane to that in which the principal l^miph-sac stands to the mucous 

 membrane of the smooth surface. There is, however, between the lymphatic 

 cavity and the mucous tissue a superficial stratum of musctdar fibres. 

 In fresh preparations it can be easily made out that the deeper muscular 

 fibres, which are nearest the attachment of the tongue, form a single 

 bmidle on either side of the middle line, spread out towards the double 

 tip in finger-like processes ha™g spaces between them. Through these 

 spaces the two hmiphatic sacs freely communicate, so that when liquid is 

 injected into either sac, the other also becomes distended. 



