240 MICROSCOPY. 
If the frog is a large one, the mesentery can be spread out so 
as to afford the most magnificent exhibition of capillary circula- 
tion, with a distinctness, and under an amplification which will | 
excite the greatest admiration and astonishment in any one who 
has only seen it hitherto in the web, or the tongue. 
The objectives of a high power ought to be more tapering at 
the end than our American makers usually furnish them. In this 
respect, some of the foreign objectives are superior. It would be 
very little more trouble to make the higher powers at the object 
end but little larger than the front lens, and thus infinitely more 
convenient for work than with the large flat surface which most of : 
them now present. In fact, with a 4 or ,4 American objective, “ 
ordinarily made, it would be impossible to approach sufficiently 
near to the mesentery to focus on the smaller capillaries without 
striking some of the larger bloodvessels. If nothing more 
be done, the front set at least might be mounted in 4 little pre 
jecting tip or nose; and if those who are ordering objectives wil 
insist upon this, I doubt not the opticians will do their part. —™ 
L. Suirn. 
Tus New Erecrine Arrancement.— In the January number 
of this Journal, and also in the Monthly Microscopical ca 
of the same date, Dr. Ward describes “ A new erecting arrani . 
ment especially designed for use with Binocular Micron 
The arrangement proposed by Dr. Ward will undoubtedly work 8 
he proposes, but cui bono? It is an axiom in microscopy: = wae 
as in other pursuits, that the simplest means of accomplishing 
an end is the best. Dr. Ward’s arrangement is complicated a 
troublesome, and unless all the lenses are well made and T his 
centred, definition will be injured. Dr. Ward is correct ee 
observation that the “erectors usually furnished [italics am si 
are not good and the use, otherwise satisfactory, of ag o 
- vision.” The first clause is correct because “ the erectors 
furnished” reverse, counteract or destroy all th 
which the opticians have taken so much pains to int jsion. 
the objectives. The second clause refers to pinocular Hi i 
This has been completely accomplished by Tolles’ binocular © “ 
piece which has been in use and before the public more real 
years. Without any change from, or addition to, fee er 
construction or use, it gives an image erect, binocular ane 
