412 Mr. Bowman on the Parasitical Connection 



siderably. A longitudinal section of one of these cells may not 

 inaptly be compared to the folds within the helix of the human 

 ear ; but its usual form may be seen in the magnified perpendi- 

 cular section, Tab. XXIII . Fig. 7 ; and its cross section in Fig. 8. 

 10. & 11. The compound microscope shows every part of its sur- 

 face to be lined with innumerable oval transparent glands or pa- 

 pillae, some sitting, but for the most part raised on pedicels of va- 

 rious lengths, and all pointing towards the centre of the cavity. 

 These glands are so minute as to be barely visible with the 

 lowest magnifier of the compound microscope. Their situation 

 may be seen in Fig. 10: & 11 ; and their shape, very highly 

 magnified, in Fig. 12. They are marked by four longitudinal 

 depressions, which indicate as many septa or valves within, the 

 intermediate spaces being hollow (see d. and e. of Fig. 12.); but I 

 have not been able to ascertain whether the apex of the gland, 

 or the pedicel, be perforated. They have a very beautiful ap 

 pearance under the compound microscope, either in a trans- 

 verse section of the cell, or when the lining of the cell is viewed 

 as an opake object. On account of their extremely delicate 

 texture, they soon shrivel up as the section dries. 



Though satisfied, from the elaborate structure of these secret 

 chambers, that they were destined to perform some important 

 office, and that they must, some way or other, have an exterior 

 communication, it was not till after repeated observations and 

 many tedious and unavailing efforts, that I had the good fortune 

 to discover it. If the longitudinal section of the leaf and one of 

 its cells (Tab. XXIII. Fig. 7.), or the more highly magnified part 

 of it (Fig. 9')i be attentively examined, a very narrow interstitial 

 opening or passage may be traced from a. inwards, between the 

 incurved lower edge of the leaf d, and the underside of the leaf- 

 stalk e, and leading into the inclosed wider space within, b. 

 This inner space (a cross section only of which can be shown 



in 



