370 
NOTES AND MEMORANDA. 
Zeiss s New yV Oil-immersion Objective. — Mr. A. Schulze “ finds 
the optical qualities of this new lens in every respect equal to that of 
the the angular aj^erture being about the same. The working dis- 
tance is about one-thirtieth inch, and the magnifying power with a 
Ross A eye-piece fully 680 diameters. The field is perfectly flat, and 
tlie brilliancy and definition leave nothing to be desired, whilst the 
resolving power is extraordinary. All the finer diatomaceous tests, 
such as Ampliipleura pellucida, &c., are resolved with the greatest ease 
and with the utmost distinctness ; and although I have hitherto failed 
to see both with the and the oil-immersion lenses more than 
with Powell and Lealand’s excellent new formula, or some other first- j 
class water-immersion lenses, yet I see everything better and easier • | 
than with the latter. For the resolution of the markings on diatoms j 
no better lenses could be desired than these oil-immersion lenses. 
... It is to be regretted that Professor Abbe and Mr. Zeiss deem it 
inadvisable to undertake the construction of microscopical objectives of J 
yet higher power on the oil-immersion principle. This they do, how- j 
ever, both on account of practical difficulties in the production of still < 
smaller lenses, and because no greater angular aperture could be 
gained than those of the ordinary largest angled water-immersion 
lenses.” * 
Theory of the Action of Bacteria in Anthrax. — In applying the data 
furnished by the experiments communicated to the Academy to the 
comparative study of the lesions which I have observed in different I 
species of animals, I consider that it is possible to deduce from them I 
a general theory of the action of bacteria introduced into an organism. 
The following is a summary of the theory : — 
Anthrax is due to the existence of a parasite which lives and is 
reproduced in the blood and fluids of living animals, which acts through ‘ 
its physical qualities, and through the substances which it secretes or 
exudes, or the formation of which it provokes ; these substances are 
soluble, and possess inflammatory properties more or less intense 
according to the animals which nourish the bacteria. The difference 
in activity of the phlogogenic matter has not yet been exjDlained : it is 
possible that it depends on the peculiar properties of the blood of the 
animals in which the parasites are developed, but some experiments, 
unpublished as yet, lead me to think that they may be owing to poly- 
morphism. 
When the bacteria produce a matter wdiich is only slightly inflam- 
matory, they act more especially by their physical properties, and 
cause death by the obliteration of the capillary vessels of the essential 
organs ; such is the case with the rabbit, the sheep, and the guinea- 
pig, where these lesions are almost exclusively met with. To the more 
intense phlogogenic properties correspond vascular lesions of another 
order ; the rupture of the capillary vessels and effusions of blood more 
or less considerable which exist simultaneously with the vascular . 
obliterations, as is seen sometimes in sheep, and always in the horse 
and the ass. Lastly, the inflammatory properties may predominate, and 
* ‘ English Mechanic,’ vol. xxviii. p. Iff. i 
