Tue MIcROscoPE. 31 
copists as to the exact shadings and markings of test and other 
objects, notably those having lines meeting or crossing at various 
angles, are possibly due to the fact that they are not seen through 
the same or optically similar eyes, and one being almost or 
practically free from astigmatism and the other having it devel- 
oped to a much greater degree, thus making it utterly impossi- 
ble for the observers to see alike. 
The remedy proposed by Mr. Gundlach, viz: Eye-pieces 
with the eye-lens of an asymmetric or cylindrical form so as to 
correct or neutralize the asymmetry of the eye, is in harmony 
with his well known earnest efforts to improve and build up the 
science in which he is a workman of superior skill. 
While the plan is quite feasible and very excellent in op- 
tical results, there are several and serious objections that may 
be mentioned. 
The first, and perhaps most tenable one, is the fact that 
while the eye-piece would perfectly suit the person for whom 
it was made,—one eye at least—not another one in several 
thousand could use it unless it was so constructed as to admit of 
having the eye-lens, the asymmetric part, readily removed and 
replaced by a symmetrical one, and the optical results would 
not be commensurate with the trouble and expense involved. 
Complicated combinations of spherical and cylindrical 
lenses, requiring plus and minus lenses of both kinds, ranging 
in focal distance from six inches in extreme to seventy or one 
hundred in mild cases, and skill and experience are necessary to 
correct astigmatism. How then can the ordinary microscopist 
bring order out of confusion by experimenting with three eye- 
glasses? 
It would simplify and improve matters if the astigmatic were 
to have the formula for a lens neutralizing his asymmetry, for 
instance, thus :—36 cyl. axis 180°, sent to an optician and have 
made a small lens with a steting of thin brass so constructed as 
to slip on the top of the eye-piece, over the eye-lens and as close 
to it as possible. The slight details of convenient construction 
readily suggest themselves to the optician. 
If the microscopist uses the eye-piece of one maker the acces- 
sory, for such it is, fits each and all of them as they are brought 
