260 ON AILANTHINE. 



nian flora, two of the members of that of the Carboniferous system and 

 indications of a mesozoic flora, in beds whose order of superposition is 

 so distinct. It further affords an excellent illustration of the geological 

 importance of the study of fossil plants, which first threw light on the 

 age of these beds, and without which, in the absence of well-marked ani- 

 mal fossils, their position in the series of deposits would still have been 

 uncertain. 



Art. XX. — On Ailanihine. The silk yielded by the Saturnia or 

 Bonibyx Cynthia, with Remarks on the Ailanthus glandulosa 

 or False Varnish Tree of China. By Robt. Paterson, M.D., 

 F.R.C.P.E., Corresponding Member of the Botanical Society 

 of Canada, &c, <fec. 



(Read before the Botanical Society of Canada, January 26, 1863.) 



There are few individuals who have not watched the interest- 

 ing changes which take place in the larvae of the Bombyx Mori, 

 or common silk-worm, from the point of its exit from the egg 

 until it has reached its full butterfly existence ; and many there 

 aie who have been sadly disappointed at the mortality which 

 comes over a brood of silk-worms in a single night from some 

 cause or causes unknown and consequently equally unremediable. 

 Such epidemics are continually occurring in China as well as 

 Europe, and constitute one of the greatest obstacles to the intro- 

 duction of the culture of the silk-worm into this country. What 

 occasions this sudden decimation of these insects has never been 

 determined, but has long led to a wish, on the part of those inter- 

 ested, that a more hardy breed of silk-producing worms could be 

 introduced into Europe, even although the produce was coarser, 

 and of a worse colour, than the ordinary mulberry silk. 



Recent information, through our missionaries in China, leads to 

 the knowledge that there is a considerable number of worms 

 used by the Chinese, in different districts, for the production of 

 silk of various qualities and coarseness. These varieties of silk are 

 used in China principally for the manufacture of dresses for the 

 peasantry. Of late, however, some of these have reached this 

 country, and have been considered durable and excellent. Could 

 we but rear such silk in our country, as we hope shortly to be able 

 to show that we can do, how much of the present overwhelming 

 distress, which is visiting our manufacturing districts in conse- 

 quence of the American war, might be avoided. Such material, 



