Natural History. 393 



sages found in the herbaceous plants, these are the medullary rays of 

 which an example is offered by the hemp, which may be seen by 

 three sections, one transverse, one down the axis of the plant, and a 

 third parellel to it, but on one side. The asclapias syriaca offers a 

 similar structure. 



M. Amici believes that in all vegetables, water and their own fluids 

 pass into the vessels through pores in their respective membranes, 

 which the eye cannot discover, but which many facts prove to ex- 

 ist. He affirms the integrity of the vessels during the whole exist- 

 ence of the plant, and denies any change in their nature. As to the 

 question whether the spirals of tracb.Ee are themselves tubular, and 

 conduct sap, he thinks it undeterminable until the optical means we 

 possess, are such as to develop the structure of the vegetable mem- 

 brane, for the dimensions of the spiral of the trachae does not exceed 

 the thickness of the membrane of the other tubes, in which as yet no 

 one has found vessels containing fluids. 



2. Dry Rot. We have been favoured by Mr. Baker of Hamp- 

 stead, with some valuable observations on the above subject, which 

 want of room prevents our publishing in detail. He adduces a 

 number of instances, in which the following application effectually 

 prevented the disease, and cured it where it had made considerable 

 ravages. 



Take two ounces of white arsenic in powder, dissolve it by boil- 

 ng hi one gallon of soft water ; if boiled in an iron or tinned vessel, 

 add half an ounce of copper filing?, but if in an untinned copper vessel 

 the filings are not necessary ; to a quart of size and half a pound of 

 common tar, add a small quantity of fresh-slacked stone-lime, sifted 

 pretty fine, beat them well into a paste, which should be then nicely 

 dissolved with the above solution, gradually adding during the pro- 

 cess (by small portions,) as much more of the pulverized lime as will 

 give the whole a proper (rather diluted) body, to be laid on with a 

 painter's brush. New work when finished as a preventative should 

 be dressed with the composition, at least twice after well drying the 

 first coat ; old work as a curative when removed and repaired, (such 

 as diseased wainscott) should be perfectly dried by exposition to 

 the air, and then well dressed on its back before it is returned to its 

 place. 



3. Insects in Amber. — M. Schweigger having very attentively ex- 

 amined the insects contained in the bits of yellow amber of the coasts 

 of Prussia, and which at first sight might be thought to be the same as 

 the present insects of that country, has found that they in fact often 

 belong to the same genera, but not to the same species as those living 

 in the present day. Among the small number of insects described 

 and figured in the work of this author, we observe in particular an un- 

 known species of scorpion, and a spider which differs from all the 



