28 PROGRESS OF MICROSCOPICAL SCIENCE. 



externa, and, on the other hand, between the nervous contents witli 

 the processes of the ganglion cells. — Vide Report of the Forty-sixth 

 Meeting of the German Scientific Association. 



Growth of the Fruit-pedicel of Pellia epiphylla. — Herr Askenasy 

 described at the above-mentioned meeting the growth of the fruit- 

 pedicel (seta) of Pellia epiphijlla. It was divisible into two periods, 

 during the first of which there was continuous multiplication of cells 

 by division, but scarcely any elongation. On the other hand, during 

 the second period, which lasts only from three to four days, cell 

 multiplication stopped, but the length increased from 1-2 to 80 milli- 

 metres. This w-as accomjianied by a total consumption of the starcli 

 contained in the cells. 



A Mode of Microscopically Examining the Growth of Plants is given 

 as follows in a recent number of ' Silliman's American Journal ' : 

 — It says that the author of the invention, after alluding to Miiller'a 

 use of a transparent net and Sach's auxonometer, describes a simple 

 device for reaching the same end. He emj^loys a glass tube, of con- 

 venient size, to be placed in the field of a microscope, and allows the 

 root or other part of the plant to grow in this. Of course the part 

 must be fixed at some point, either with cork or with damp bibulous 

 paper. The free end of the root has now room for growth, either in 

 water or in moist air — preferably the latter. The tube can be sub- 

 jected to a known degree of heat by the use of Sach's hot-air chamber 

 (described on page 644 of the Lehrbuch). The tube having been 

 fixed on the stage can be accurately observed every few minutes, or 

 after a longer time, a micrometer being all that is needed for deter- 

 mining distances. The errors which may result from these observa- 

 tions are frankly alluded to. This simple method is particularly 

 adapted to the investigation of the effect of light on growth, as the 

 whole apparatus is completely under control of the observer. 



Occurrence of Starch in Sieve-cells, — Dr. Briosi communicated to a 

 recent number of the ' Botanical Zeitung ' a paper on this subject. 

 A brief recapitulation of previous researches by Hartig and Hanstein 

 is followed by an account of recent original observations. In all 

 plants examined, when a violet colour is produced in sieve-cells by 

 iodine in iodide of potassium, the requisite magnifying power shows 

 that there are always minute granules which present a sharply-defined 

 spherical outline. Even in the so-called solutions of starch in cells, 

 these minute granules can be detected. They remain unchanged after 

 treatment with alcohol and ether. In sections treated according to 

 the method of Bohm-Sachs (that is, heating with a solution of potash, 

 washing, and neutralization with acetic acid, and then addition of a 

 dilute tincture of iodine) the starch granules of the sieve-cells are 

 coloured deeply violet, even when the large starch granules of adjacent 

 cells have become broken down into a paste. If the sections are 

 placed in dilute acids (hydrochloric or nitric) and then treated with 

 iodine in iodide of i^otassium, the starch granules are coloured blue or 

 deep violet. The minute granules swell up, but still preserve their 

 spherical form, even when the other granules have become a paste. 



