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SCIENCE-GOSSIP. 



CONDUCTED BY J. H. COOKE, F.L.S., F.G.S. 



To whom Notes, Articles and material relating to Microscopy, 



and intended for Science-Gossip, are, in the first instance, to 



be sent, addressed "J. H. Cooke, Thorndale, Lincoln," 



Crystallization of Oils. — In his report to the 

 Secretary of the Department of Agriculture, 

 U.S.A., Mr. Thomas Taylor, the microscopist to 

 the Department, has illustrated a very ingenious 

 freezing-box for use with the microscope, whereby 

 the various oils and their acids may be crystallized 

 so as to obtain micro-photographic views of their 

 respective crystalline arrangement. Another ad- 

 vantage offered by this invention is that by this 

 method objects in natural history mounted in 

 varnish or other media may be thrown on a screen 

 and photographed. 

 In the accompany- 

 ing copy of his 

 drawings, a repre- 

 sents the micro- 

 scope, B the freez- 

 ing-box made of 

 brass or of German- 

 silver, and attached 

 to the substage 

 of the microscope 

 by means of two 

 clamps, one on 

 either side of the 

 box. b is a separate 

 view of the appa- 

 ratus ; a and a 1 

 represent tubes, one 

 of which supplies a 

 freezing liquid, the 

 other carries it off. 

 A pail to receive 



the waste liquid is in readiness, and is connected 

 in the usual way by means of rubber tubing ; 

 c is an opening through the centre of the box, 

 which admits of the transmission of rays of 

 light to the object under investigation. The 

 freezing may be used repeatedly, or until it ceases 

 to be cold enough for the purpose. Ammonia, 

 ether, or any other freezing liquid may be used. 



Ch aulmugr a Fat Crystals. — Numerous experi- 

 ments have been conducted by Mr. Taylor with 

 this apparatus, all with gratifying results. The 

 very peculiar forms which the fat of chaulmugra 

 oil assumes in crystallizing led to the discovery 

 that it was an hitherto undescribed fat. It was 

 mounted in the usual way. It was then sufficiently 

 heated to make it liquid, and was placed quickly 

 under the microscope. As it cooled, crystalliza- 

 tion rapidly progressed. At first globular masses 

 were observed, each one showing, under polarized 

 light, a well-defined cross. As soon as these 

 globular masses have formed, a second crystalliza- 

 tion takes place, proceeding from the globular 

 accretion in the form of an elongated spreading 

 fan. (Figs, i and 2 on next page.) 



Distribution of Hydra. — Alluding to the 

 distribution of Hydra in his recent address to 



Taylor's Freezing-Box and Microscope. 



the Manchester Microscopical Society, Professor 

 S. J. Hickson remarked that if hydras be examined 

 we shall find that in the summer and autumn 

 months they produce small swellings or protu- 

 berances on the sides of their body-walls, and each 

 of these contains a small brown body. A careful 

 examination with the microscope shows that these 

 brown bodies are really eggs which are covered by 

 a tough, horny shell. This in itself is a remarkable 

 fact, for in the large group of animals to which 

 Hydra belongs, including all the Hydroids, jelly- 

 fishes, corals and sea-anemones, this is the only 

 genus that possesses such a covering on the eggs. 

 Moreover, Hydra is the only freshwater Coelenterate 

 which has a world-wide distribution, and if these 

 two facts be placed side by side we must arrive at 

 the conclusion that Hydra owes its wide distribution 

 to the fact that it produces eggs which are so well 

 protected that they can resist the dangers of a 

 passage through the air. 



Mushroom Spores. — In the identification of a 

 species of the Agaricini it is of the greatest 

 importance that the exact colour of the spore 

 should be determined. These spores are very 

 variable in size, shape, and colour, but they are 



tolerably constant 

 at maturity in the 

 same species, and 

 even in different 

 species of the same 

 genus. The size of 

 the spores varies 

 from one hundredth 

 to a few thousandths 

 of a millimetre in 

 diameter. Their 

 shape is almost 

 always spherical in 

 the young plant, but 

 afterwards becomes 

 ovate, ellipsoidal, 

 fusiform, reniform, 

 smooth, stellate and 

 sometimes tubercu- 

 late. A study of 

 the spores enables 

 one to differentiate 

 between the edible and the non-edible species. 



Microbes of Disease. — Diseases have their 

 local habitations, says the " Saturday Review." 

 Some, like tropical animals and plants, live only in 

 the tropics ; some, like consumption, are gradually 

 spreading over the whole earth ; others, like leprosy 

 and small-pox, are gradually becoming limited in 

 their distribution and may actually be tending to- 

 wards extinction. Again, there are regions to which 

 diseases have never reached. On the summits of 

 high mountains and in the circumpolar snowfields 

 the earth and air and water are barren of the 

 microbes of disease as they are of animal life. In 

 a country like Britain, thickly populated for many 

 centuries, and with the freest circulation of popula- 

 tion, it cannot be doubted that every yard of 

 surface contains the germs of the more common 

 diseases, and the native of some newer land 

 brought over here would fall a victim to our 

 plague-stricken soil. By generations of a 

 destructive elimination we have become highly 

 resistant to our native diseases, just as the 

 Gold Coast natives are less susceptible than 

 we are to their own local diseases. But we 

 are not fully protected, and cancer and consump- 

 tion — two of our common scourges — still take a 



