ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
147 
of the glass plate through the boring of the right binding-screw. Lastly 
a cover-glass D mounted in a metal frame is brought over the glass 
plate. The frame has on each side projecting pieces which fit into 
vertical grooves so that the cover-glass, either by its own weight of 
1 • 45 grm. or by means of the two screws S, can bo pressed down upon 
the preparation on the glass plate. 
For observations on the unstretched muscle, the muscle is simply 
laid upon the glass plate, and covered by the cover-glass. For inves- 
tigating the effect of stretching on the diffraction phenomena, the 
muscle is fastened to the hooks H, or preferably one end is fastened 
to the steel hook on the left, while the other is attached to the string 
which passes over the pulley to the scale-pan, in which different 
weights can be placed so as to vary the tension. For the observation 
of the diffraction phenomena during contraction and tetanus, the muscle 
is stretched in the same way. To conduct the current a fino wire 
connects the binding-screw through which the thread passes with the 
hook by which the thread is attached to the muscle. In these experi- 
ments the general arrangement for observing the spectra was the same 
as before. 
The distances of the first spectrum from the undiffracted image in 
the case of the sartorius were as follows : unstretched, 35 divisions ; 
weighted with 2 grm., 30 divisions ; weighted with 10 grm., 25 divisions ; 
for a hyoglossus at its maximum tension, 17 divisions. 
Compression of the muscle has no marked influence on the distance 
of the spectra. Contraction of the muscle causes the spectra to approach 
one another. No displacement of the spectra occurs on exciting the 
muscle when at its maximum tension. 
The late Mr. G. F. Dowdeswell, E.R.M.S. — The late Mr. Dowdes- 
well, who was some time a member of our Council, and for several years 
a constant attendant at our meetings, died in October last at the age of 
56 years. His career was somewhat varied, for after an education 
at Eton and Magdalene College, Cambridge, he entered the army ; ho 
served through the Mutiny and the Chinese campaign of 1860-6. The 
later years of his life were devoted to Histology and Bacteriology, and 
he published on both subjects a number of important papers, partly in 
our Journal, in the Proceedings of the Royal Society, and elsewhere. 
Among the subjects in which he specially interested himself we may 
note the structure of spermatozoa and the “ cholera bacillus.” Mr. 
Dowdeswell was also a Fellow of the Linnean and Chemical Societies. 
Good Advice ! — The Editors — Professors E. D. Cope and J. S. 
Kingsley — of the ‘ American Naturalist ’ are often asked what journals 
of biology a college with limited funds should take. As may be 
supposed, they place their own journal first ; “ next in importance is the 
Journal of the Royal Microscopical Society.” It is not for us to 
deny this. 
* Amer. Natural., xxv. (1891) p. 89.5. 
