326 



SCIENCE GOSSIP. 



is to take a good cork, and through it cut a hole, 

 say, § to ■§ of an inch in diameter, and then cut it 

 into slices, say, J to J of an inch in thickness. Pro- 

 cure a piece of toughened " parchment paper," such 

 as is commonly used for packing tobacco, biscuits, 

 or other articles, and fix a circular disc of the paper 

 across the bottom of each slice of the perforated cork, 

 attaching it with gold size, brown cement, shellac 

 varnish, or any other suitable cement. In this way 

 a number of little boxes are made, whose sides are of 

 cork, but through whose bottoms diffusion of liquids 

 can take place. 



Take up the water containing the desmids with 

 the pen-filler already mentioned, and place it in one 

 of the little boxes. Then float the box in a jar of 

 glycerine, which should be stoppered or covered with 

 a tight-fitting cap. The water will gradually diffuse 

 through the toughened paper into the glycerine, and 

 the glycerine will diffuse, but more slowly, into the 

 box. In the course of about forty-eight hours or 

 more the water will be replaced by nearly pure 

 glycerine ; but, owing to the unequal rate of diffusion 

 •of the two liquids, the glycerine will stand at a 

 lower level in the box than the water did originally. 

 It is therefore advisable to place a fair quantity of 

 water in the box to start with. When the trans- 

 ference of liquids has taken place, the glycerine 

 containing the desmids may be taken up with the 

 pen-filler, and either at once placed in a cell ready 

 for mounting or transferred to a small specimen tube 

 for future use. There is no harm, however, in leaving 

 the desmids in the cork float for an indefinite length 

 of time, if it is not convenient to proceed with them 

 at once. 



The desmids 1 treated in this way preserve their 

 colour fairly well, and exhibit little or no contraction, 

 provided that they were placed in sufficient water to 

 start with, and. in slides of Closlerium many speci- 

 mens show the remarkable bodies at the tip whose 

 movements in live specimens are so interesting. 

 Traces of these bodies may even be seen in the 

 accompanying illustrations (figs. 3 and 4) ; in the 

 original photographs, from which the blocks were 

 made, they are well shown. The method applies 

 equally well to other algae, such as Volvox and 

 Spirogyra. The latter, being so common, affords a 

 convenient test object for showing its efficacy before 

 experimenting on rarer algae. The arrangement of 

 the chlorophyll bands, so characteristic of the genus, 

 is in general beautifully preserved, the only effect on 

 the colour being a slight darkening, which appears 

 inevitable. 



There is little or no waste of glycerine, as the same 

 jar of glycerine may be used for several gatherings in 

 succession. When it has become too diluted it may 

 be concentrated by evaporation with the aid of heat, 

 and protection from dust is not essential, as the fluid 

 has to pass through the paper membrane before 

 reaching the desmids. It might be useful to try 

 whether a similar method could be used with glycerine 

 .and gum, which possesses many advantages over 



glycerine as a mounting medium, though the passage 

 of gum through the parchment paper would probably 

 be a very slow matter. Mr. JVoad Clark experienced 

 some difficulty in taking the photographs for the 

 illustrations accompanying this paper, owing to the 

 frustules becoming tilted on one side when the slides 

 were placed in a vertical position. This displace- 

 ment could, no doubt, be obviated by the use of 

 glycerine and gum or some such medium, which 

 hardens instead of remaining fluid. 



( To be continued. ) 



LIFE UNDER OTHER 



CONDITIONS. 



By Geoffrey Martin. 



TK If st month's SciKNCE-Gossir (p. 291) I dis- 

 cussed the possibilities of life at far higher tem- 

 peratures than are now prevalent upon the earth. I 

 concluded that if such forms of life were possible, 

 the central or "linking" element must have been 

 silicon, and not carbon ; further, that such life pro- 

 bably first originated when the earth was : one great 

 siliceous ocean of white-hot fluid. In this ocean, 

 under the enormous temperatures and pressures 

 that held sway, strange compounds must have been 

 ever forming and decomposing ; these reactions 

 must have been continually going on during an 

 enormous period of time. Is it therefore absurd to 

 believe that at some one instant of all this time, and 

 out of all the infinite number of compounds con- 

 tinually forming in billions per second, it was 

 possible for the proper elements to come together 

 but once, in such a position and in such a way as to 

 generate the ever.decomposing compound that formed 

 the first living being ? Grant but this one primordial 

 act of creation, whereby the germ of life inherent in 

 matter could thrill into existence, then we can con- 

 ceive that with no day of creation the whole order 

 of creation could mechanically evolve.^) 



If in the primordial living matter silicon once 

 played the part now played by carbon, it might be 

 asked : How is it that it is no longer present in the 

 organism ? But the answer comes naturally if we 

 consider the nature of life as enunciated last month. 

 I stated that life proceeds by the continual de- 

 composition of very complex compounds, and that 

 their unstability is a function of the temperature, 

 which, if too high, breaks them down completely, 

 and renders their transitory existence impossible, 

 while, if too low, it renders their spontaneous de- 

 composition impossible, both conditions being equally 

 fatal to life. Further, the temperature at which 

 elements are capable of yielding such complexes in 

 a state of continual decomposition differs for different 

 elements. Thus, for carbon it is between o° and 



(1) Welby, " Nature," October 1S94, p. 44. 



