ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
791 
special collet, which grips it from beneath, so that there cannot be any 
shake ; it is not merely £ roughly secured by a stop-pin/ as ‘ Microsco- 
pist ’ assumes. In fact, his remarks consist of an expression of super- 
ficial opinion, formed from an incorrect conception of the build of the 
instrument. 
In proof of our assertion as to the rigidity of the form of substage, 
as fitted by us to the Edinburgh Student’s Microscope, we may say that 
the sale of this class of instrument has now run into hundreds, and it is in 
frequent use by many leading microscopists, from whom we have 
received letters expressing great satisfaction with the rigidity of working 
parts. Further, a great deal of the demand for the instruments is from 
the very men that c Microscopist ’ considers are best able to ‘ formulate 
the desiderata of a student’s Microscope ’ — viz. the teachers in medical 
schools. From these, throughout the world, we have received orders, 
not only for ones and twos, but for “ ties,” and in nearly every instance 
the instruments have been preferred on account of their rigidity and the 
convenience and perfection of substage. 
If any one required a substage on a fixed tail-piece we should supply 
it ; but never, since we have made the Edinburgli Student’s Microscope, 
have we been asked for such. — W. Watson & Sons.” 
“ Allow me to supplement my letter (see above) by a few observa- 
tions, which I trust will forward improvements in the construction of 
students’ Microscopes. 
I have suggested that responsible teachers in medical schools 
should combine and authoritatively formulate the desiderata of a student’s 
Microscope, and that the laws of demand and supply would do the 
rest. 
On the question of the need of such combined action for this 
purpose, I hardly expect a dissentient voice. But as to the best 
means of bringing this action to a focus, that is matter on which I must 
only touch with diffidence. The fact that Mr. G. C. Karop, secretary of 
the Quekett Microscopical Club, avows his special interest in the subject 
would point clearly in his direction as a possible centre of action. No 
great difficulty should be found in forming a committee of men of similar 
tastes and aims, who would cordially strive to bring out a Microscope to 
meet the modern wants of students both as to efficiency and economy. 
Such a committee would require the co-operation of a skilled 
mechanician, having considerable manufacturing resources at his 
command, and who would boldly face the outlay of developing what 
would be recommended. The prospect of the large business that would 
naturally follow upon the successful production of a student’s Micro- 
scope, under such favourable auspices, would, no doubt, be quite sufficient 
to bring forward the rigkt mechanician. 
It may be asked why the requirements of students at this moment do 
not induce an optician to produce exactly what is wanted? On this it 
may be said that up to the present time the teachers in medical schools 
have never attempted any concerted action in the matter ; they have 
teen content, individually, to make suggestions here and there to the 
opticians, and these latter have only felt safe in carrying out the sugges- 
tions when they emanated from an influential man whose personal 
authority sufficed to insure a demand for the instrument large enough to 
