Dec. 1, 1866.] 



HAEDWICKE'S SCIENCE-GOSSIP. 



281 



MICROSCOPY. 



Scalariforji Ducts. — A short time since a 

 friend of mine showed me some very fine scalari- 

 form ducts from ferns, and he said they had been 

 obtained by prolonged maceration (a year or so) in 

 hydrochloric acid. As I have found out a much 

 shorter method of preparing them, I send it, think- 

 ing it may be useful to many who have neither seen 

 them nor yet know how to get them. I simply boil 

 the fern-stalks, cut into short lengths, in a solution 

 of caustic soda (about 30 grains to the ounce of 

 water) for a quarter of an hour or so ; then take 

 them out and crush them well in a mortar, replace 

 them in the solution, and boil again for five or ten 

 minutes, when they will be found to have become 

 quite soft. The cuticle can then be picked out and 

 thrown away. Allow all the fine fibres to settle, 

 and pour off the dark-coloured fluid, and boil them 

 three or four times in water, adding to the last 

 water a few drops of hydrochloric acid, which 

 whitens the mass considerably. On crushing a 

 little of this fibre in a live-box, the scalariform 

 ducts may be easily seen, their position noted, and, 

 on removing the cover, picked out. In this manner I 

 have obtained them from fern-stalks cut at Woking 

 in the early summer, which had become as dry and 

 hard as wood. Some of the ducts I have isolated 

 in this way are -^ of an inch long. The ladder- 

 like markings are best seen when mounted in 

 fluid. Care must be taken in pouring off the 

 various waters, as I have found some of the best 

 ducts in them, on allowing time for settling. The 

 same process will answer equally well for preparing 

 the fibre from flax, New Zealand flax, &c, as well 

 as obtaining the spiral vessels from rhubarb, &c. 

 Although microscopists are credited with great 

 patience, yet twelve months is a long time to wait 

 for a result, so I hope this paper may be the means 

 of adding an additional object to many cabinets. — 

 John Davis, Stowmarkel. 



Gun-Cotton Muslin. — A piece of Gun-Cotton 

 Muslin {i.e. muslin converted into tri-nitro cellu- 

 lose) forms a very pleasant polariscopic object, 

 especially if the " red and green" selenite is used. 

 It must be mounted in balsam. — John Davis. 



Movements of Diatomace.e. — I was reading 

 the other day a paper in the Popular Science Review 

 on the movements of the Diatomaceae, which does 

 not altogether satisfy me, and upon which I shall be 

 glad of further information. I have for years thought 

 they moved by means of some part of the body 

 which they could protrude something like a snail ; 

 but not from the raphe, at least in the Pleurosigma. 

 The shell of this, I think, is bivalve, as I have occa- 

 sionally found the two sides apart ; one instance 

 of which I met the other clav, of which I send a 



sketch, as it appeared partly turned round. Seen 

 on the flat side, there was, of course, no appearance 

 of any separation ; and seen edgeways, there was 

 merely an angular opening like No. 2. I have also 

 now and then, when looking at the Pleurosigma 

 sideways, seen a curious movement along the edge 

 of the shell, as if it opened at one end, gradually 

 extending to the other, and closing again as it 

 went on. This I attributed to the undulating 

 movement of the foot. There is evidently some- 

 thing protruded from the shell, as, watching some. 

 small species the other day, when the pointed end 

 approached a small body, before it quite touched it, 

 it drove it on before it : and that it could fix itself 

 was shown by its drawing a foreign body with it 

 when it moved backward. This moving a piece of 

 anything before it, and drawing it after it, without 

 the shell touching, I saw in numerous instances, but 

 it did not take place when the edge of the shell 

 approached anything. — E. T. Scott. 



New Zoofhyte. — The Rev. Thomas Hincks, 

 while dredging last autumn in Swanage Bay, 

 found a new zoophyte, belonging to the Sertidaridte, 

 which he refers to a new genus, under the name of 

 Op/riodes mirabiUs. It was not uncommon in from 

 five to eight fathoms water. One peculiarity 

 noticed is the webbed tentacles, a character which 

 had only hitherto been observed among the Campa- 

 nularidcB. Technical description and figures are 

 contained in the " Annals of Natural History," for 

 November, 1S66. 



Coloured Tracts of the Ocean. — On an 

 average sixty-four animalcules of one kind were 

 found in every cubic iuch of water submitted to 

 examination, and on the supposition that they were 

 equally numerous throughout the body of coloured 

 water, Mr. Scoresby computed that a surface of two 

 square miles, and fifteen hundred feet deep, con- 

 tained no less than twenty-three thousand millions 

 of millions of animalcules belonging to one species. 

 And, in order to form a more definite idea of this 

 vast multitude, he remarks that the number of years 

 required for eighty thousand persons to count them 

 would be equal to the period that has now elapsed 

 since the creation of the world. — Brocliesby's Micro- 

 scopic World. 



Pollen Granules.— In a single blossom of Dan- 

 delion, I counted no less than 243,600 pollen 

 granules ; a flower of Pa?ony gave on an average 

 3,054,000, and in an entire Rhododendron plant the 

 pollen grains amounted to the wonderful number of 

 72,620,000.— Dr. A. H. Hassall, in Ann. Nat. Hist. 



PodubtE. — At the November meeting of the 

 Quekett Microscopical Club, Mr. S. J. Mclntire 

 read a paper on this subject, which created con- 

 siderable interest, three or four species of these 

 curious creatures being exhibited alive. 



