November, 1902.] 



KNOWLEDGE. 



261 



to submerged rootlets of trees growing near the edge of the 

 water. Attached to the fine stems of Cnrrhi'sium, Zoothumtiiitm 

 and other stalljed colonies of Vorticella, the very much more 

 minute, but beautiful, colonies of Collared Monads: OkIosIhii, 

 etc., are often found, and deserve a good look with the higher 

 jiowers. 



In canals and lakes where Cristatella has been abundant 

 during the summer, their spiny stadoblast may now be found 

 liberated and often in large masses floating near the edge of the 

 water which lies opposite to the direction of the prevailing wind. 

 These should be collected and ])laoed in a jar full of water with 

 some Anacharis in the warm room at home, where they will 

 hatch by the end of December or January, and the beautiful 

 young Polyzoa can be seen emerging from their box-shaped 

 prison. 



Fixe Aii.iusTME.NTS.— In a former number (July, 1901) some 



fine adjustments of recent construction were described, and 



reference was made to one which Jlessrs. Swift & Son were 



introducing, the details of which, at the 



time, were not ready for publication. 



The adjoining figure will enable the 

 ])rinciples of its construction to be at 

 once ajipreciated, its action depending on 

 a lever of the second order, which com- 

 municates an exceedingly slow rate of 

 movement, and at the same time allows 

 of the use of a coarse operating screw, 

 which obviously would not be so liahle 

 to wear with constant use as a fine one. 



A fine adjustment of this description 

 goes a long way to elevating a microscope 

 from a tool which magnifies to an instru- 

 ment of precision, and is a feature 

 which, there is no doubt, will bring its proper reward to its 

 inventors. 



While on the subject of fine adjustments, a new two-speed 

 arrangement may be incidentally referred to. Descriptions 

 have previously appeared iu these columns of the original device 

 which was introduced by Messrs. R. L*t J. Beck, and now an 

 altogether different one, possessing novel features, has been 

 put on the market by Messrs. AV. Watson & Sons. 



In Messrs. Reek's form, the two milled heads were mounted 

 on one centre, i.e., one operated through the other ; in Jlessrs. 

 Watson's form their ordinary lever is used, and for the e.xtra 

 slow movement a second lever is joined to the main one, and 

 acts in conjunction with it, a second milled head separately 

 mounted being fitted for effecting the movement. In effect, 

 the operation of the second lever is the .same as an extra long 

 lever would produce. 



Considerable limits in the rate of movement are possible by 

 merely altering the pitch of the thread or the point of couUict 

 with the lever. In any case it is worthy of notice as a new 

 device in microscopic adjustments. 



Cellular Stru( Tt'RE.— The interest and information which 

 arise from the examination of cell structures and contents is 

 such as to make it worth while for the ordinary worker to 

 pursue the subject in some degree for himself. Who has not 

 been struck on examining chlorophyll or protoplasmic structure 

 for the first time V and the interest is materially increased by 

 the knowledge of the controversies which have occurred, and 

 experiments which have been made for so many years in 

 connection with this particular subject. 



A simple method of examining for oneself is as follows : 

 Take an onion, cut it in half and separate the layers with a 

 pair of forceps ; clinging to each scale is a deUcate vegetible 

 membrane. This is carefully removed and a piece cut from it 

 with a pair of scissors, about f of an inch diameter. This will 

 then have to go through a fixative of 30 per cent, alcohol, iu 

 which it is immersed for about three minutes. The fi.xed 

 specimen is then transferred to a 1 per cent, watery solution of 

 iodine for five minutes. This stains the nucleoli, nuclei, 

 protoplasm and cell-walls a yellow or brown. The specimen is 

 subsequently rinsed and mounted. 



IE the protojjla.sm in the cell is to be the special object of 

 examination, some of the fixed pieces should be pLaced for five 

 minutes in an 80 per cent, solution of alcohol, then transferred I 



to a 1 per cent, aqueous solution of metbj'l violet for three 

 minutes. This will produce a violet staining effect, which will 

 show not only the cell-wall, nucleus and nucleolus, but also the 

 protoplasm as a distinct mass with a clear space between it and 

 the cell-wall. 



If it is desired to double stain the sections, they should be 

 transferred from the fixing solution to Delafield's hajmatoxyhn 

 for ten minutes, rinsed iu water, then placed in hydrochloric 

 acid 10 drops, water lOOcc, in which they should remain until 

 they fade to a salmon pink colour ; transfer to water until they 

 a.ssume a light blue colour, immeree in a 1 per cent, aqueous 

 solution of eosin for .\ minute, rinse and mount. These 

 processes produce a nucleus stained a rich blue and other 

 structures pink. 



The subject may also be examined fresh in water on a slide 

 having an excavated centre, when the nuclei and cell-walls will 

 appear in faint outline. 



Wavted, a Microscope Table.— There are a largo number 

 of working microscopists who are greatly restricted for space, 

 and are consequently unable to devote a room for their work, 

 or even to have many really essential fittings. To such, a table 

 which would at once combine and afford all the convenience for 

 microscopical work would be a boon. Medical men nowadays 

 especially have frequently to prepare specimens of sputum and 

 other micro, subjects for immediate examination, and, under 

 ordinary circumstances, each individual item of the various 

 processes has to be specially looked out, the microscojje set up 

 and arranged, all at the cost of considerable time and trouble. 



Many amateur microscopists would work a great deal more 

 with their instruments if it were not for the trouble of having 

 to look everything out and prepare it for working, this alone 

 often occupies as long or longer than the time at disposal for 

 actual work. 



What is wanted, therefore, is a table which shall jjermit of 

 the microscope being left in readiness for work, and so arranged 

 that either daylight or artificial light may be immediately 

 available. There should be suitable drawers or fittings for 

 lense.s, condensers and micro, accessories ; proper fittings for 

 re-agents, wash-bottles, troughs, etc. ; drawers for mounted 

 specimens, and in addition a space which shall be dust-proof, 

 but not air-proof. In addition, if some convenient device could 

 be suggested for having a supply of water, together with a small 

 basin or sink, the convenience would be increased. 



It may be that many readers have given thought to such a 

 matter as this, or may be disposed to do so. I should be glad to 

 receive suggestions or drawings of a comprehensive table, and 

 would arrange that two or three were published in these columns. 



Seeing that photo-micrography has now become so much a 

 part of a microsoopist's equipment, the desirability of including 

 space for a camera, etc., in connection with the table might also 

 be considered. 



Covers for Micro. Specimens, etc. — I am indebted to a 

 reader for kindly sending to me a sample of a very neat cover, 

 which would, I believe, be found advantageous to many working 

 microscopists. This particular one is sufficient in size to cover 

 a 3 by 1-inch slip, and is of the kind used by watch-makers for 

 protecting their work ; larger and smaller sizes can be obtained. 



In the workroom one is constantly wanting something of the 

 kind for protecting watch glasses, dissecting dishes, staining 

 cells, and preparations generally ; this would just seem to meet 

 the need. It has the special advantage of being ornamental as 

 well as useful, the handle being of cut glass of very neat design. 



The sender of this states that this was obtained from a 

 wholesale watchmaker in Clerkenwell. 



NOTES AND QUERIES. 



C. S. T. — The most likely people to give you information as 

 to the various materials for grinding rocks are Messrs. Cotton 

 & Johnson, 14, (ierrard Street, Soho, W. Have you tried 

 Carborundrum ? 



W. P. B. — The best book on the microscope is " The Micro- 

 scope and its Revelations," edited by Dr. Dallinger, of which a 

 new edition has recently been published. Of the simpler and 

 more elementary works, " A Popular Handbook to the 

 Microscope," by Lewis Wright, costing 2s. 6d., is very good. 

 To use your .Student's Petrological Microscope for general 

 purposes, it is only necessary to withdraw the analyser prism , 



