AN HOUR AT THE MICROSCOPE. ' 91 



obtained, and then the two forms of cells, parenchymatous and 

 spiral, are well seen, as also the openings of the latter. It is a curious 

 sight to see Infusoria passing in and out of these holes, and 

 making themselves quite at* home in the restricted domain of a 

 cell of Bog-Moss. Professor Huxley, in an article in the British 

 and Foreign Medical Review, has written to the effect that by 

 carefully dissecting the growing point in Sphagnum it would be 

 found that a stage would at last be reached where no difference 

 could be traced between the sinuous, narrowly-elongate cells 

 containing chlorophyll, and the large spiral-bearing air-cells which 

 they surround ; though these are so very different in the mature 

 condition. An early enunciation in fact of the law of differentia- 

 tion, which has helped so materially in the recent march of 

 scientific research. 



Sphaeraphides from Echinus Vesnagii.— John Quekett 

 preferred maceration for the purpose of obtaining Sph?eraphides, 

 and I can certify that it is the safest way. Liquor Potassae may 

 be used, but it is powerful stuff; I am afraid of it. " Pulvis 

 Rhei " of the druggists will furnish very fine Sphgeraphides ; and 

 sections made of the root will show them /// situ capitally, along 

 with the rich red-brown cells bearing the fragrant resin which gives 

 this drug its officinal value. Quekett ascertained, and stated, the 

 curious fact that the number of Sphaeraphides in Rhubarb root 

 may be taken as an index of its quality, — the best Turkey being 

 very rich in them, but the dressed-up English, sold by sham 

 Turks, containing comparatively few. The same genial climate 

 which nourishes the cathartic products, is alike favourable to the 

 growth of these crystalline accompaniments, both in abundance 

 and in size. There is a good article under the head of " Raphi- 

 des," in the Micrographic Dictionary, which should be consulted 

 by all would-be workers at the subject. If practicable^ Professor 

 Gulliver's various papers should also be read : they are scattered 

 through various periodicals, some difficult of access, and many, 

 alas, buried and all but lost to science in the proceedings of a 

 local Microscopical Society ! 



Trichina Spiralis.— Could anything more conclusively show 

 the value of the microscope, than that it enables us to find out 

 the cause, otherwise mysterious and inscrutable, of one of the 

 most dangerous and deadly diseases ? We take a bit of infected 

 muscle, some y^Awch square, and a mere film in thickness, and 

 find in it perhaps 70 of these death-inflicting creatures ! The 

 literature of Trichina and Trichinosis is now a copious one ; the 

 best way to get at it will be to consult a medical friend ; or we 

 may read a most complete account of it in an old volume of the 

 Transactions of the Pathological Society of London, by Rainey 



