420 Foreign and Miscellaneous Intelligence. 



tion of which is a matter of conjecture, and the actual structure 

 of which has given rise to much difference of opinion. These 

 organs have received the names of pores, or glands, or stomata, 

 according to the views of different observers ; and while one class 

 of botanists has considered them of unknown function and struc- 

 ture, others have contended that they are of the nature of pores, and 

 that their office was, according to the one, to facilitate evapora- 

 tion to the others, to assist in the process of respiration. Their 

 function is obviously of so obscure a nature, that no direct experi- 

 ments are likely to demonstrate exactly what it is ; but their structure 

 is a point upon which observation may be expected to cast some light. 

 Mr. Bauer long ago represented these organs in the wheat, as perfora- 

 tions opening into a minute subcutaneous cavity, and as destined to 

 afford a direct passage into the interior of a plant for those minute 

 fungi, whose ravages are so well known in the form of what the far- 

 mers call the mildew in corn. Other observers have, however, doubted 

 whether the supposed perforations always existed ; and Mr. Lindley, 

 in his lectures in the University of London, has repeatedly expressed 

 his difficulties upon the subject. The fact is, that they are so minute, 

 the tissue of which they consist is so exceedingly transparent, and it 

 is so difficult to examine them, except by the aid of transmitted light, 

 that it is not, perhaps, possible to determine positively in all cases 

 whether a perforation exists or not. Mr. Robert Brown has re- 

 cently published some observations upon them, from which it is to 

 be collected that, in the opinion of that distinguished observer, the 

 stomata are rather of the nature of glands than of pores, and are un- 

 doubtedly in many cases imperforate evidently having in their disc 

 a membrane which is more or less transparent, sometimes opaque, or 

 very rarely coloured. The existence of colouring matter in the 

 stomata is the only circumstance that could have enabled an observer 

 to prove their imperforate nature ; for, in colourless membranes, such 

 as those of Crinum, in which the stomata are particularly large, the 

 best microscopes, employed under the most favourable circumstances, 

 show nothing but an apparent orifice, closed up occasionally by the 

 dilatation of two glandular bodies placed beneath it. Mr. Brown 

 states, what was certainly a very unexpected fact, that these bodies 

 will often, in proteaceous plants, by their figure and position, or 

 magnitude, with respect to the meshes of the cuticle, determine the 

 limits or even affinities of genera, or natural sections. 



7. SMUT IN CORN. 



This substance, which has been sometimes considered a mere organic 

 disease, but more usually a parasitical plant, analogous to that 

 which causes the mildew and the rust, and which has been described 

 under the names of Reticularia segetum, Uredo segetum, and Uredo 

 carbo, has been lately the subject of a particular inquiry on the 

 part of M. Adolphe Brongniart, who thus describes the parts in 

 which this malady is found, and who adopts the opinion that it 



