156 Miscellaneous. 



brown colour, as well as those seven the pore-grains of which assume 

 a blue tint, — which grains iodine proves to be real starch. It would 

 be remarkable indeed, if the substance in the former were not also 

 of a similar nature to starch, — if it were not in fact isomeric with 

 starch. 



2ndly. It would also be most remarkable, if plants of the same 

 family, the nectaries of which agree with one another in situation 

 and structure, should in some cases contain starch in the nectary 

 and in others a different substance. Amongst the Labiatce, for in- 

 stance, it is indisputable that the nectaries of Mentha arvensis and 

 Clinopodium vulgare contain starch. It would be extraordinary in- 

 deed if the contents of the nectaries of many other Labiatce, as of 

 St achy s sylvatica and arvensis, Prunella vulgaris, Lamium album, &c, 

 were not also starch, although they are turned brown by iodine, for 

 their nectaries are in all other respects exactly similar to those of the 

 first. 



3rdly. The elements of starch (C 1 *, H 10 , O 10 *) form also with the 

 same number of atoms three or four other substances, dissimilar in 

 their chemical and physical properties, viz. cellulose, inuline, dex- 

 trine, and lichen starch. Schleiden, however, in his * Wissenschaft- 

 liche Botanik,' 1846, does not consider lichen starch as a distinct 

 substance, although Mulder in his • Chemistry of Vegetable and 

 Animal Physiology,' which I have before me only in an English 

 translation by Fromberg, without date, regards it as a chemically 

 distinct body. When will the time come when chemistry will state 

 results on these important substances which will meet with general 

 acceptance ? It is certain, at all events, that the chemical combina- 

 tion of C 12 H 10 O 10 constitutes a most variable substance. Although 

 we may never be able by direct analysis to prove the identity of 

 the granular matter in the nectaries, which is coloured brown by 

 iodine, and the formula C 12 H 10 O 10 , there is nothing to prevent us 

 from assuming the identity, and concluding that the contents of the 

 nectary, which are coloured brown by iodine, are isomeric with 

 starch. From this substance, therefore, and the nitrogen contained 

 in the pollen and ovules, the sugar of the nectar results. 



Cringleford, near Norwich, April 1849. 



On the Intimate Structure of Articular Cartilage. By Dr. Leidy. 



As is familiar to every anatomist, articular cartilages always 

 fracture in a direction perpendicular to their surface, the broken 

 edge presenting a striated appearance in the same direction. This 

 character the older anatomists ascribed to a fibrous or columnar 

 structure of the cartilage, like that of the enamel of the teeth, while 

 histologists at the present day consider it as dependent upon the 

 vertical arrangement of the rows of cartilage- cells, although it has 

 been suspected to depend upon some ultimate arrangement of the 

 matrix or intercellular substance not yet detected. In some late 

 observations upon the structure and development of articular carti- 

 lage, through means of an excellent microscope, made for me by 



* I quote from Mulder's 'Chemistry of Animal and Vegetable Physiology.' 



