NOTES ON RECENT RESEARCH. 



257 



is pouring out at the bottom of the flue. Then of course the air has been 

 forced out by the vapour, when the valve is closed. It is left closed for 

 three days ; then the doors are opened that the vapour may escape, when 

 all the weevils will be dead. As a rule seed pest enter the seeds in the 

 field. Treatment therefore is more effective if made as soon as possible 

 after harvesting." 



Treatment for Clothes Moths. 



The various insects which infest clothing, furs, &c, may be more 

 conveniently and surely destroyed by an application of carbon bisulphide 

 than by anything else. Moth balls, camphor, &c. may do some good by 

 deterring the females from depositing their eggs upon articles treated 

 therewith, but they have no killing power whatever, and if the eggs have 

 already been deposited the young larvre will feed after hatching as 

 though there were no moth balls or camphor present. Carbon bisulphide, 

 however, will not only keep the adults away, but it will also destroy all 

 stages of the pest infesting the goods. When woollens, furs, and the like 

 are stored away for the summer, they may be placed in a tight paper- 

 lined trunk, a large packing box, or such receptacle. When all are stored 

 away place on top a shallow dish holding a few ounces of the liquid, 

 spread some newspapers over the top, and cover tightly. If the box is 

 tight no further attention will be required, but if not it will insure 

 safety to repeat the dose every few weeks through the hot weather. It is 

 an excellent plan to provide a large tight packing-chest having a small 

 sponge, bunch of cotton waste, or some such thing on the inside. The 

 chest may then be kept tightly closed and carbon bisulphide may be 

 poured through the hole upon the absorbent as may be necessary. Plug 

 the hole with a cork and all is secure. The cost of such an arrangement 

 will very soon be saved by the convenience and security of the protection 

 thus afforded. Carpets, rugs, robes, &c. can be easily rid of all pests by a 

 few days' exposure in such a box. The disagreeable odour is much less 

 persistent in the goods than is that of moth balls or tarred paper. If 

 pure carbon bisulphide is used, it will not stain or injure the most delicate 

 articles. — B. N. 



Internal Phloem. 



Gelsemium sempervirens, Structure and Development of 

 Internal Phloem. By Caroline B. Thomson, B.S. (Contr. Bot. Lab. 

 Phil. vol. ii., No. 1, p. 41 ; pi. 9). — Detailing result of observations 

 made during the winter of 1897-8. 



The internal phloem arises primarily as four longitudinal strands, an 

 integral part of leaf -trace bundles. 



The origin of internal phloem simultaneously with the protoxylem and 

 external phloem, so that the leaf-trace bundles are bicollateral from the 

 first. 



The internal phloem patches are bounded internally by a two-celled 

 phloem sheath. 



They grow centrifugally by means of a medullary cambium, the inner 

 and older layers in time becoming crushed and obliterated. Death of the 

 pith occurs early in the first year. Continued disintegration of pith and 



s 



