By Professor Lindley. 



303 



in the epiphloeum of such tubers, and which, in a natural state, is 

 locked up in the cells of which that part consists. Independently 

 of these observations, it is not to be doubted that frost does split 

 the tissue of plants. I saw the youngest shoots of Erica medi- 

 terranea, cinerea, and others shivered into thousands of pieces in 

 the Horticultural Society's Garden, on the morning of the 20th 

 of January. The branches of Melaleucas were rent to their points 

 at Carclew. Several cases, among others that of the common 

 holly, were observed at Claremont, where the bark was split, and 

 rent asunder from the wood below it ; and Sir Oswald Mosley 

 has given me the following instance, which occurred under his 

 own observation. " An oak tree, growing upon the south side 

 of a hill, in a sheltered situation, in Knightly Park, near Burton- 

 upon-Trent, in the County of Stafford, was rent in the severe 

 frost of last winter in two different places, to the height of 13 ft. 

 3 in. There was an interval of 11 in. between the two shakes, 

 which were each of them one quarter of an inch wide, and extended 

 in depth to the heart of the tree. The girth of the tree is 6 ft. 

 10 in., and as soon as the frost went the openings closed again, and 

 the tree is now as flourishing as ever." To these cases many more 

 might be added. 



The organization of woody tissue appears to be affected, but not 

 by laceration. If a frozen and unfrozen transverse slice of the stern 

 of Hibiscus Rosa Sinensis be placed, side by side, upon the field 

 of the microscope, it is obvious that the diameter of the tubes 

 of the wood and liber is considerably less in the former than in 

 the latter ; this appears to be owing to an increase in the thickness 

 of the sides of the tubes, which has the effect of diminishing their 

 calibre. 



The expulsion of air from aeriferous organs, and the introduction 

 of it into parts not intended to contain it, is a striking pheno- 

 menon. Every one must have remarked that when a leaf has been 

 frozen to death, it changes colour as soon as thawed, acquiring a 



