es 
AND THE ULTIMATE POWER OF THE MICROSCOPE. 583 
primitive origination of the Entozoa, and which have not been men- 
tioned in the memoir, I will only remark that these bodies are metho- 
dically inoculated into every animal being in which they have hitherto 
been discovered, which implies nothing wonderful, but only much that 
is obscure, and which hereafter may be gradually cleared up by an in- 
creased power of the microscope. 
2. On the perception of the smallest bright bodies I have had an op- 
portunity of obtaining a few more results. On pressing small globules 
of quicksilver on a glass micrometer, I easily obtained smaller globules 
of +45 to s7'55 Of a line in diameter. In the sunshine I could only dis- 
cern the reflection of light and the existence of suchglobules as were 335 
of a line in diameter with the naked eye; smaller ones did not affect my 
eye either in sunshine or with a Chevalier’s reverberatory lamp. I 
however remarked, at the same time, that the actual bright part of the 
globule did not amount to more than 53, of a line in diameter. Spider- 
threads of 5,45," in diameter were still discernible from their lustre. 
3. I have lately made some experiments on the dust of diamonds, and 
found that a diamond superficies of >, of a line in diameter presents a 
much more vivid light tothe naked eyethan one of quicksilver of thesame 
diameter. I have not yet been able to find smaller particles of diamond 
dust possessing a good lustre. The smallest particles were from >;'55 
to 3,57 of a line in diameter ; but even under the microscope no lustre 
was to be perceived. This, perhaps, was owing to the treatment. The 
result of these supplementary observations is, that fluid metals, since a 
small part only of their globular superficies shines strongly, make per- 
ceptible only very small particles of light ; that in proportion much 
smaller lamina, especially diamond lamina, may be at least as easily 
discerned as considerably larger metallic globules. Whether the pro- 
portion is as 1 to 3, further investigations must teach us. Particles of 
light having a linear form constitute the utmost limit ofthe power of 
vision; and the luminous or light-reflecting corpuscles are the fixed 
stars of the microscopic world. 
