Nov. 1, 1S66.] 



HARDWICKE'S SCIENCE-GOSSIP. 



257 



to spare the few plants at that time left on the 

 Bartlow Hills, as, he said, so many persons got up 

 the roots and took them away as memorials of the 

 spot, that he feared the plant would soon become 

 extinct there. I have no doubt it has long since 

 ceased to grow there. In the year above named I 

 did not see more than half-a-dozen plants, if so 

 many. Now, the villagers having long been accus- 

 tomed to get up the plants for visitors as "Dane's- 

 blood," would naturally, when they had eradicated 

 the plant, not be willing to tell fresh visitors that 

 the true " Dane's-blood " no longer grew there, but 

 would endeavour to persuade them that the Cam- 

 panula glomerata, which they would see growing 

 there, was the "Dane's-blood." The usual name 

 for this plant, as every one knows, is the "Pasque 

 Blower; " but growing, as it did formerly, on the site 

 of the burial of the Danes at Bartlow, and being of 

 a deep reddish-purple, it was called by the villagers 

 "Dane's-blood." 



Professor Babington, in his "Flora of Cam- 

 bridgeshire," remarks on the great number of 

 plants in that county, chiefly, however, marsh 

 plants, from reclaiming the fens, which had become 

 extinct since the days of Relhan. As the "Pasque 

 Plower" is not a marsh plant, I hope this has not 

 become eradicated, but it was not very commonly 

 met with even at the time I speak of. — T. Salwey. 



MICKOSCOPY. 



Dissecting Troughs. — In your August number 

 is a cheap dissecting-trough by Mr. Gedge. Being 

 in want of one myself this spring, I made mine of a 

 piece of kamptulicon, by merely turning up the 

 edges and fastening with the Indian rubber cement. 

 It is very light, and holds the pins even better, and 

 obviates the necessity of the loaded cork. — John 

 Davis, Stoiomarket. 



Illumination of Opaque Objects. — I have 

 lately adopted a new and, I think, improved method 

 of illuminating opaque objects. I simply take an 

 ordinary slide, bind the edges, and gum a piece of 

 red paper on one side, and a piece of lightish blue 

 on the other. On a similar slip I fasten white and 

 black on either side. My opaque objects are 

 mounted like transparent ones, that is, with a 

 circular hole in the top and bottom covering papers. 

 By placing one of the covered slides on the stage, 

 and the object over it, and illuminating in the 

 ordinary way, a very pleasing result is obtained, 

 especially if the colour complementary to the object 

 be used. In this way the palate of the whelk 

 (mounted dry) and most pollens, especially that of 

 the Hollyhock, are very good with the blue back- 

 ground. The Aetea anguina on the red weed 

 with the blue slide is very pleasing ; a double con- 



trast being obtained, the white zoophyte on the red 

 weed and that on the blue background. By using 

 the white slide, many j "transparent" objects (il- 

 luminated as opaque) are seen very well, the ap- 

 pearance being similar to that when the white cloud 

 illuminator is used. The black paper must, of 

 course, be " dead." By alternating these slides 

 the appearance of an object can be varied at plea- 

 sure. A revolving disc would answer this purpose. 

 — John Davis, Stowmarket. 



Removing Dbied Cuticles. — The simplest and 

 best manner is by ordinary maceration, which will 

 be very easily accomplished. The plan I have 

 adopted is as follows : — The leaves are placed in 

 common soft water, in any kind of vessel that will 

 allow of their being covered ; they are then left for 

 a week, or perhaps a fortnight, and if at the end 

 of that time are not much more flexible, should the 

 water be discoloured, I change it for fresh, and 

 again leave them, looking at them from time to time 

 to see how they progress. As soon as the leaves have 

 the appearance of being "soaked" through with 

 water, you will do well to try how far the process of 

 maceration has gone on, which can be done thus : — 

 Put your finger and thumb into the water, and, 

 holding a leaf between them, begin gently to move 

 the finger and thumb in contrary directions. If the 

 object of maceration has been attained, it will now 

 be found that the cuticles rub backwards and for- 

 wards, and at once you find that they are separated. 

 If not, put them back into the water, and leave 

 them again till you find they part from each other 

 when rubbed as above described. The next process 

 is to cut the leaf across the middle, and, by means 

 of a sharp penknife, scalpel, or pair of fine scissors, 

 cut open the edge, whicb is done in a manner some- 

 what in the fashion in which anew book is cut open. 

 If they do not separate completely, they must be re- 

 turned again to the water until they do. When sepa- 

 rated (and the separation is best done in the water, 

 and if the cuticle is a very thin one, it is almost an 

 impossibility to divide the cuticles unless they are 

 done underneath the surface of the water), if they are 

 put in a large-mouthed bottle, and gently shaken 

 about, the cuticle will often be found to require no 

 further cleaning ; but sometimes the inner tissues 

 will stick to internal parts of the cuticle, and then 

 it is necessary to gently float it out quite flat on a 

 white plate or piece of glass; and then gently 

 raising one end, so as to allow the water to leave it, 

 a fine camel's-hair brush is very gently used to re- 

 move the decayed tissue adhering to it, which, with 

 care, can be done. It is now rinsed in water several 

 times, to get it quite clean, and finally floated on 

 to the glass slide in scrupulously clean water, and 

 left to drain quite dry, when a glass cover can be 

 put over it, if dry-mounting will suit it ; or any 

 other style of mounting can be adopted, as the 



