pet Brome ea On the Podura Scale. 67 
and the peculiar fitness of the Magnesium light for photographing 
the animal tissues, and those objects generally which require the 
use of ground glass when sunlight is employed, would appear to 
have escaped the observation of these accomplished gentlemen, and 
to have remained unnoted until the publication of my Report. 
Army Mepicat Museum, 
MicroscoricaL SECTION, 
June 4th, 1870. 
| Appended to his paper, which is really a Report to the Surgeon- 
General of the U. 8. army, Dr. Woodward sends two illustrative 
photographs. The first, which represents the 6th square of the 
Moller’s type-plate of the Diatomacez, taken with Wales’s 14-inch 
objective, arranged to give thirty-five diameters, will serve for com- 
parison with the photographs of the same object with the same 
lens, taken by Sunlight, and by the Electric and Magnesium lamps, 
which were published with his former Report, and are we believe 
in the possession of the Royal Microscopical Society. The second 
represents the Navicula Lyra, taken with the Powell and Lealand’s 
immersion ,},th, arranged to magnify 1000 diameters. Col. Wood- 
ward has presented us with very excellent specimens of these, and 
has sent duplicates to the Royal Microscopical Society, and to Dr. 
Maddox, of Southampton.—Ep. M. M. J.] 
I1i.—Cursory Remarks on the Podura Scale, Lepidocyrtus curvi- 
collis, and Degeeria domestica, or the speckled variety. 
By R. L. Mappox, M.D. 
A rew brief remarks are offered to the readers of the Journal on 
the above scales, as slight explanations of fourteen photographs to 
be seen, through the liberality of Mr. Baker, optician, at his esta- 
blishment, 244, High Holborn, London. 
The present time being the period of recess, hence the impossi- 
bility of early brmging the photographs before the Fellows of the 
Society in the usual way has induced me to thus afford every 
facility that they may be seen by those who take an interest in the 
subject. 
"The question of structure has yet to be determined by the con- 
tending parties ; hence at the present time I shall merely copy the 
remarks appended to each picture, and what I consider to be the 
view given in the photograph. To attempt to explain each would 
trespass too largely on the pages of this Journal. 
No. 1.—Podura scale (test), view of the ribbed structure generally. 
No. 2.—Podura scale (test), view approaching the optician’s test 
appearance. 
