326 



SCIENCE-GOSSIP. 



MICROSCOPY 



Study of Fresh-water Alg.e. — With the 

 advent of spring the lovers of nature are enabled to 

 sally forth under favourable conditions which have 

 been denied them during the long winter months, 

 and many will no doubt be turning their attentions 

 to new fields which have hitherto had but passing 

 thoughts. It is the object of these notes to suggest 

 the study of that most interesting section of the 

 vegetable kingdom, the fresh-water algae. The 

 tyro will find the happy hunting-grounds of these 

 small organisms almost universal, and need never 

 take an excursion without returning rewarded. 

 First, I would say a few words as regards the 

 apparatus necessary. All that is requisite is a few 

 corked test-tubes, and a wide-mouthed bottle that 

 can be fitted on to the end of a stick. A useful 

 addition to this is a small piece of apparatus 

 consisting of a muslin ring net, which can be 

 affixed to the stick in the same manner as the 

 bottle, and is represented in the subjoined outline 



sketch, a represents a ring of brass wire about six 

 inches in diameter ; to the lower part is fixed a glass 

 tube c , open at both ends ; the top of the tube is fixed 

 to the muslin net b ; and the lower end, which has 

 the mouth turned back (the same as the upper end), 

 permits a piece of muslin (d) to be stretched over the 

 opening and secured by an elastic band. This 

 apparatus will be found very useful in collecting 

 small organisms floating in the water, such as the 

 volvox, etc. The presence of any such algae is 

 quickly determined in small ponds by the aid of the 

 net. A student's microscope with one inch objective 

 will be necessary to determine the different species. 

 The first question, perhaps, which will be asked is : 

 " Where are the best spots for seeking the algae ? " 

 and the answer is, wherever there is water, such 

 as ponds, quiet streams, damp places, wet rocks, in 

 greenhouses, or near factories where warm water 

 escapes in quantities. Almost everyone has 

 noticed the green, slimy patches in still water ; 

 and what microscopist has not admired the more 

 generally known species such as the Diatomaceae, 

 Desmids, etc. ? As regards the plants themselves, 

 their form is very varied, and according to the 

 excellent work by Dr. M. C. Cooke, there are 

 about twenty orders, although the real nature 

 of some is doubtful. Some species can only be 

 determined during fructification, and are exceed- 

 ingly interesting ; as for instance the Zygnemaceae, 

 which are filamentous algae found universally. 

 The filaments in some species are about the 

 size of a hair and of a rich green colour. Each 

 filament is divided throughout its whole length 

 into separate cells by septa. The chlorophyll 



in each cell assumes the shape of a spiral band. 

 At certain periods these algas will be observed in 

 the different stages of fructification : first, two 

 filaments may be seen lying side by side, then a 

 small tube will be pushed out from each cell, 

 meeting one similarly formed from the opposite 

 filament ; these tubes meet at last and the septum 

 of each disappear, there being formed a tubular 

 bridge connecting opposite cells. The contents of 

 the cells in one of the filaments will then pass 

 over into the cells of the neighbouring filaments, 

 and oval or round spores will be formed ; these 

 zygospores at length escape, and eventually, after 

 an active state, pass into the resting stage and 

 produce new plants. Numerous other examples 

 could be given showing the interesting nature of 

 these plants, but the above will be sufficient for 

 these notes, which, it is hoped, may lead some 

 readers of this journal to take up the study of this 

 interesting section of botanical research. — R. L. 

 Hawkins, Park Houses, Willesden Green. 



Seasonable Objects for Microscopists. — The 

 spores of Equisetaceae, which are easily obtained in 

 the spring of the year, will be found exceedingly 

 interesting objects if placed on a glass slip and 

 examined under the microscope with a one-inch 

 objective. Each of these spores has two pairs of 

 elaters or elastic fibres, which, when exposed to 

 moisture, twist and curl about in a most extra- 

 ordinary manner, the object of their movement 

 being the fertilization of the embryonal corpuscle. 

 The fructifying organs of the mosses are also 

 interesting objects for microscopic examination at 

 this time of year, and if carefully prepared by 

 washing and soaking in glycerine, and then 

 mounted in glycerine jelly will make permanent 

 objects of great beauty ; as all the fresh green tint 

 of their leaves will be preserved. Our ponds and 

 streams will also furnish many good objects if 

 carefully hunted, and there are probably few 

 microscopists who do not delight in examining 

 these wonderful specimens of nature. — •/. C. Webb, 

 32, Henslowe Road, Dulwich. 



Symbiosis and the Microscope. — I have not 

 had the advantage of reading Mrs. Nuttall's paper 

 on the above subject, referred to by Mr. Johnson 

 (ante page 306), but I am enclosing a short paper 

 to the Editor which may be of some use. The 

 subject is too wide for detailed treatment in a 

 magazine article, but Mr. Johnson will find much 

 information in Strasburger's "Practical Botany," 

 Goebel's "Outlines of Classification" and Sach's 

 "Physiology of Plants," all of which authors give 

 copious references, mostly to German works, how- 

 ever. — Jas. Burton, 9, Agamemnon Road, IVtst 

 Hampstead. [The article referred to will appear 

 next month. — Ed. S.-G.] 



Miller's Caoutchouc Cement. — For the 

 December number of Science-Gossip, Mr. Cole 

 states that methylated spirit is the solvent for this 

 cement. This, indeed, is printed on the lable, but 

 is certainly incorrect. The spirit dissolves only 

 one constituent, the shellac, of the cement, but not 

 caoutchouc, which remains at the bottom of the 

 bottle undissolved. Caoutchouc is soluble in very 

 few fluids, but one of these is chloroform, and 

 therefore a mixture of equal parts of chloroform 

 and absolute alcohol forms a perfect solvent for 

 Miller's cement. Strong methylated spirit could 

 be substituted for the absolute alcohol, only the 

 former does not mix quite so well with the chloro- 

 form. The mixture keeps very well in a glass- 

 stoppered bottle. — C. F. Rousseht, F.R.M.S., Castle 

 Street, Regent Street, London. 



