40 ORGANOGRAPHY. BOOK 1, 



the lio-ht of glands. Necs von Esenbeck and Link deny the 

 existence of any perforation in the stomates, and consider 

 that the supposed opening is a space more pelkicid than the 

 surrounding tissue, and that what seems a closed up slit is the 

 thickened border of the space. Link further adds, that the 

 obscuration of the centre of the stomates is caused by a pecu- 

 liar secretion of matter, as is plainly visible in Baryosma 

 serratum. {Elementa, p. 225.) To the views of these writers 

 is to be added the testimony of Brown {Suppl. prim. Prodr. 

 p. L), who describes the stomates as glands which are really 

 almost always imperforate, with a disk formed by a membrane 

 of greater or less opaqueness, and even occasionally coloured ; 

 at the same time he speaks of the disk being, perhaj^s^ some- 

 times perforated. 



In tlie midst of such conflicting testimony, an observer 

 necessarily finds much difficulty in fixing his opinion. 



Li no plants are stomates larger than in some Monocotyle- 

 dons ; they are, therefore, the best subjects for examination 

 for general purposes. In Crinum amabile they evidently con- 

 sist of two kidney-shaped bodies filled with green matter, 

 lying upon an area of the cuticle smaller than those that sur- 

 round it, and having their incurved sides next each other. 

 In some, at the part where the kidney-shaped bodies come in 

 contact, there is an elevated ridge, dark, as if filled with air, 

 and having its principal diameter distinctly divided by a line. 

 (Plate III, fig. H.) In this state the stomate is at rest : but 

 in others the kidney-shaped bodies are much more curved ; 

 their sides are more separated from each other ; and there is 

 no elevated ridge : at their former line of contact there is an 

 opening so distinct and wide as to be equal to half the dia- 

 meter of one of die kidney-shaped bodies ; tliis, I presume, is 

 the stomate open. That what is described to be an opening, 

 is really so, seems to be demonstrated by the following tests : 

 — L It is more transparent than any part of the most trans- 

 parent portion of the cuticle ; 2. It admits transmitted light 

 without interruption ; as is seen by gradually augmenting the 

 magnifying power by which it is viewed, when the opening 

 continues transparent, notwithstanding the great loss of light 

 that attends the use of very high powers in compound mi- 



