258 DR M'INTOSH ON SOME POINTS IN THE STRUCTURE OF TUBIFEX. 



probable que ces cellules versent de la bile clans la cavite" de l'intestin. II est 

 beaucoup plus vraisemblable qu'elles deVersent leur contenu dans la cavite" 

 pe>iviscerale." He reiterates this opinion in his recent beautiful and accurate 

 memoir on the Histology of the Earthworm.* Dr Gruithuisen, indeed, 

 clearly anticipated most of the subsequent observers in regard to the connection 

 between this glandular coating and the perivisceral fluid, which he termed the 

 chyle. In describing the glands which envelope the intestine of his Nais 

 (Chsetogaster) diaphana, he observes, "Diese Drlis'chen bilden das, was bei 

 hohern Thieren die Chylusdrtisen sind, und ergiessen den Chylus unmittelbar 

 in den Eaum zwischen der musculosen Haut und dem Darmcanale."t This 

 author, moreover, notes the peculiarity that in a single " Mutternaide " of 

 Chcetog aster diastropha, he found in December that the chyle-corpuscles were 

 larger than usual, and seems to think that there is a connection between chyli- 

 fication (referring to the perivisceral fluid) and generation. Dr Thomas 

 Williams, \ again, was strongly of opinion that the long coils of the blood- 

 vessels anteriorly in his Nais filiformis (probably Tubifex) and the perivisceral 

 branches elsewhere in the body of this worm, were specially intended for 

 absorbing from the perivisceral (his " chyl-aqueous ") fluid elements by which 

 the blood-proper is formed and replenished. It will therefore be seen that the 

 supposition thrown out by my friend Mr Lankester that " the yellow glandular 

 tissue" surrounding the alimentary canal "may have but little to do with the 

 secretion of digestive juices, or, at any rate, may have an additional and most 

 important connection with the production of the corpuscles of the perivisceral 

 fluid, and may serve to place that fluid in organic relation with the liquid of the 

 closed vascular system of the intestine, and the contents of the digestive tract," 

 is by no means new. It appears, indeed, to be the result arrived at by Dr 

 Fritz Batzel from an examination of the literature of the Oligochetes previous 

 to the appearance of the foregoing ; the author, moreover, assigning the peri- 

 visceral fluid the function of a communicating medium between the digestive and 

 circulatory systems. Further, I have not seen anything to support the idea of 

 Mr Lankester that the abundance or scarcity of the "granules" in the perivis- 

 ceral fluid depends on the condition of the glandular coating of the intestine 

 and dorsal vessel. The glandular investment presents the same appearance 

 whether the corpuscles be few or many, and the agglomerations of granules 

 shown by him most readily take place in such a highly coagulable fluid. For 

 my part, I have no objection to offer to any of the theories advanced on this 

 subject, so far as they rest on actual observation and not on mere conjecture. 

 In Tubifex and its allies the perivisceral fluid is an eminently coagulable and vital 



* Zeitsch. f. wiss. Zool. Ed. xix. (18G9), p. 614. 



t Ueber die Nais diaphana, &c, Nova Acta Acad. Leop. Carol. Tom. xiv. Pt. i. p. 411. 



% Report Brit. Assoc. 1851, p. 182 ; and Philos. Trans. Part ii. 1852, p. 625. 



