2 28 LANG DON. [Vol. XI. 



Conclusions. 



From the foregoing study, the following conclusions seem to 

 me to be warranted : 



I. The epidermis of Lumbricus agricola, Hoffm. contains a 



4. Smiinovv believes that some of the intraepidermal nerve-fibres surround 

 the sense-cells. Although I have searched carefully, I have failed to find any 

 evidence of such connection between these fibres and the " Nervenzellen " — i.e., 

 the sense-cells of a sense-organ. In thick sections, it sometimes appeared as if 

 the intraepidermal nerve-fibres penetrated the sense-organs, but under the oil 

 immersion such fibres were found to be always outside of the sense-organs, 

 among the supporting cells. I have preparations in which the intraepidermal 

 fibres are stained in such numbers in the tissue between sense-organs that it 

 seems to me unlikely that my failure to find fibres surrounding the sense-cells is 

 due to a failure of the stain to act on such fibres. 



5. Smirnow describes and figures the " Geschmackszellen " found by Retzius 

 ('92) in the buccal cavity. Smirnow's figures and description of these so-called 

 cells lead me to the conclusion that they are but the outer ends of ducts from the 

 gland-cells which are so numerous in this region. He says: " Der verjlingte Teil 

 der Zelle und der sich an ihn unmittelbar ausschliessende Fortsatz impriigniren 

 sich viel schwacher, als der verdickte Teil der Zelle, wobei die Impragnation mit 

 dem Silbersalz an den Randern des Fortsatzes intensiver ist, als in dem axialen 

 Telle, der heller erscheint und zum Teil von schwiirzlichen Kriimeln und Brocken 

 erfiillt ist. Unter diesen Bedingungen macht der Fortsatz den Eindruck eines 

 hohlen Gebildes, eine Rohre, deren Lumen z. T. von kriimligen Massen erfiillt ist. 

 Dieser eigentiimliche Ban lasst mich vorlaufig zweifeln an der nervosen Natur 

 dieser Gebilde." I have some sections stained by Kleinenberg's haemato.\ylin 

 which were not treated with sodium bicarbonate and which have, therefore, faded. 

 But the glands have retained the stain and stand out distinctly. I find, above the 

 pharynx, glands from which long ducts pass in a sinuous course through the sur- 

 rounding tissue to the upper wall of the pharynx. Each tube enters the epithe- 

 lium of this wall and opens exteriorly by a minute pore in the cuticula. Just 

 beneath the cuticula each duct is slightly enlarged. In fact, these tubes appear 

 exactly like the illustrations which Retzius and Smirnow give of the so-called 

 "Geschmackszellen." I find the ducts filled with minute, deeply stained particles 

 of the secretion, which would answer to the "schwiirzlichen Kriimeln " seen by 

 Smirnow ; the secretion in the enlarged apex is often clear, homogeneous, which' 

 would explain the appearance which both Retzius and Smirnow thought might 

 be a nucleus. 



Smirnow's discovery was later verified by Retzius in an article entitled " Die 

 Smimow'schen freien Nervenendigungen im Epithel des Regenwurms," which ap- 

 peared in the Anat. Anzeiger, Bd. 10, Nos. 3 and 4 (Oct. 6, 1894). In new prep- 

 arations, Retzius succeeds in obtaining the intraepidermal nerve-fibres. lie, him- 

 self, now feels doubtful concerning the nervous nature of the " Geschmackszellen " 

 (or, as he calls them in this article, the " Kolbenfasern "). He finds these back of 

 the " Mundhohle," and says : " In eine Reihe von Priiparates habe ich sie nun so 

 massenhaft gefarbt gefunden, dass ich gestehen muss, das mir zuerst ebenfalls 

 ihre nervbse Nature etwas zweifelhaft erschien." 



