12 



KNOWLEDGE. 

 FLORA SELBORNIENSIS. 



January, 1915. 



The page of Gilbert White's " Calendar of Flora " which we give this month is the first, and it is con- 

 cerned to a considerable extent with the weather. 



January, First Month. 

 25th. — The Bat mentioned is most probably the Pipistrelle {Vesperugo pipistrellus). 



February, Second Month. 

 I St. — For the Great Titmouse, Gilbert White uses the name Parus major, by which it is still known. 



CORRESPONDENCE. 



ANTISEPTIC CLOTHING. 



To the Editors oj " Knowledge." 



Sirs, — We owe to Sir William Perkin the discovery of 

 constructing artificial dyes from products of coal-tar. 

 The discovery proved to be of importance, not only in 

 dj-eing cloth, but, of still greater importance, in staining 

 microbes, making them \dsible and distinguishable. 



This discovery led to the theory of " side-chains " in 

 the microbes, and, further, the construction of that chemical 

 compound called " Salvarsan," wliich is so deadly to one 

 particular variety of spirilla. 



It has been noted that in the war, whenever serge from 

 the clothing was carried in with the shell fragment, the 

 wound was more septic than when pieces of linen were 

 carried. It may be that, the former being more spongy 

 in character than the latter, the bacteria of putrefaction 

 perhaps find a more suitable substance to lodge in and mul- 

 tiply in serge than in hnen, being a Uttle more compact. 



Is it not possible for some men of science, especially bio- 

 chemists, to find out a process by wlaich wool or woollen 

 fabrics can be made, not only aseptic, but thoroughly 

 antiseptic, so that the microbes may not find in them 

 a suitable place to lodge in and multiply ? It \\'ill be as 

 much a prophylaxis to the material worn as inoculation 

 for enteric and cholera is to a soldier. 



P. J. DAMANIA. 



Worthing. 



LETCHWORTH MUSEUM. 

 To the Editors of " Knowledge." 



Sirs, — May I be allowed, through your valuable medium, 

 to make known to readers of your paper that a local and 

 educational museum has recently been opened at Letch- 

 worth, which it is intended shall, in course of time, be 

 representative of the geology, fauna, flora, and human 

 history of North Hertfordshire and a t^velve-mile radius 

 of Letchworth, thus embracing South Bedfordshire and 

 a small part of South Cambridgeshire ? 



The museum owes its inception to the late Miss James, of 

 Haslemere, and the generosity and goodwill of Mr. Aneurin 

 \MUiams, M.P., Chairman of First Garden City, Limited. 

 It is under the management of the Garden City Naturalists' 

 Society. Donations towards the upkeep and the necessary 

 expenditure which a museum entails will be gratefully 

 received. 



It is hoped that the pubhcation of this letter will result 

 in an increased membership and an influx of visitors. Gifts 

 or loans of objects of interest from the localities mentioned 

 will be most acceptable, as \vi\\ also books devoted to natural 

 science, local industries, and topograph}-. 



I shall be pleased to forward further particulars to anyone 

 interested, or to arrange for visitors to see the collections 

 of local and educational objects at present exhibited. 



W. PERCIVAL WESTELL, F.L.S. 



Letchworth. 



TO OBTAIN THE COLOURING MATTERS OF RED ALGAE. 



By W. B. GROVE, M.A. 



It is not always easy to extract in the best condition the 

 Chlorophyll and Phycoerythrin which are contained in 

 Red Seaweeds. For that reason a description of the follow- 

 ing processes, wlaich are very successful, may be useful 

 to some who have not previously been satisfied. In order 

 to make the account complete, certain steps which are ob- 

 vious enough are included in the description. The t\vo 

 coloured solutions thus obtained appear very pure in tint, 

 and, so far as such different colours can be compared, they 

 are of approximately the same intensity. 

 {^The Alga which has been found to serve best is Rhody- 

 menia palmata, one of the abundant Dulses of our coast. 

 The quantity which can be packed in a one-pound cocoa- 

 tin is sufficient for the purpose : it should be sent from 

 the sea freshly gathered, and on the morning of arrival 

 should be divided into two equal portions, for separate 

 treatment. .\ longer delay will produce inferior results. 



Place one portion in a saucepan or beaker, with plenty 

 of water, and bring to the boil ; continue the boihng for 

 five to ten minutes, or even longer. Then rinse quickly 

 in two lots of " industrial " spirit ; pack lightly in a suitable 

 vessel, just cover with fresh spirit, and leave in the dark 

 for t\venty-four to fortj^-eight hours. On pouring off the 

 solution, it will be found to be of a deep, rich, and beautiful 

 chlorophyll-green, %\'ith blood-purple fluorescence — as good 

 a colour as is generally to be obtained from grass-leaves. 



The other portion of the Alga should be washed repeatedly 

 (ten or more times) in tepid water, until the water, after use, 

 looks as pure as before Then carefully remove all the bases 



and stalks of the fronds, and eveiy diseased and discoloured 

 part, or those which are occupied by zoophytes, and so on. 

 This can best be done with a pair of scissors. The selected 

 clean and bright-coloured laminae are then cut up with the 

 scissors into pieces about five to ten milhmetres square, or 

 less. These should be packed as tightly as possible in a 

 tall glass vessel, about one and a half to two inches wide. 

 It is convenient to place the pieces round a glass rod standing 

 in the centre of the vessel, and ram them down with a 

 suitable wooden stick. 



Then withdraw the rod, just cover the pieces with dis- 

 tilled water, see that it penetrates into even,' part (which 

 does not always happen if they are tightly packed), pour on 

 the surface four or five drops, or more, of eucah'ptus oil, 

 according to the size of the vessel, as a disinfectant, and 

 leave in a shaded place for four days at room temperature. 



The solution may then be poured off, and should be per-- 

 fectly clear ; if not, it may be filtered in the ordinary way. 

 It is of a very deep rose-pink colour, showing a remarkably 

 strong and beautiful orange fluorescence, so that by reflected 

 hght it appears to be filled with a multitude of minute 

 orange ghstening particles. If more distilled water is after- 

 wards placed in the vessel, a second but weaker solution 

 can be obtained in another four days. 



Both the green and the pink solutions will keep for a 

 considerable time — even for more than a month — in the dark. 

 Other seaweeds, Chondrus, Dilsea, Polysiphonia, Ceramium, 

 and so on, have been tried, but in all cases the results were 

 inferior. 



