272 
NOTES AND MEMORANDA. 
Lepidoptera (but not in Hymenopterous larvae) . We are tlms led to 
suppose that it has something to do with the formation of the faceted 
eyes. If it has any relation with the bundle of fibres passing from 
the optic lobe, there is nothing to indicate it. 
Secondly, the size of the olfactory lobe, with its olfactory bodies, 
correlated in insects with small antennae entirely unfit for tasting, but 
on the contrary, with a very completely developed sense of smell, is 
in the author’s opinion an excellent proof of the correctness of 
Leydig’s view that the antennae are organs of smell, whatever may be 
brought forward in opposition to it. If they are to be interpreted 
as an apparatus for detecting sounds, we, on the other hand, are 
acquainted with the finer structure of the organs of hearing in the 
Orthoptera, and know that they have no such constituted brain-centres 
as the olfactory lobes. 
Thirdly, Flogel draws attention to the wonderful and so little 
understood facts that in insects, where the lobes (“ bechers ” of 
Flogel, “ lappen,” “ gestielte korper,” &c., of Dietl) and the substance 
around them (geriist) constitute the greater part of the brain, there is 
iudeed no connection of the nerve-fibres to be found with the remain- 
ing parts of the brain, and consequently also with the oesophageal com- 
missures. The opinion that the ganglionic cells are in direct relation 
through fibres with the organs of the body is provisionally unfortu- 
nately contradicted. But where are the intermediate stations ? he asks. 
Finally, the author claims that the essay indicates the outlines of 
a future brain topography for insects, and shows that the single 
parts of the brain have their homologues in the different orders of 
insects ; consequently a ground-plan in the organization is not to be 
mistaken, and thus a comparative anatomy of the brain of insects is 
outlined comparable with that of the vertebrates, as established by 
the researches of Stieda.^ 
The Movement of Microscojpic Particles suspended in Liquids . — In 
Section A. (Mathematical and Physical) of the British Association’s 
recent Meeting, the following paper, entitled ‘ Note on the Pedetic 
Action of Soap,’ by Professor W. Stanley Jevons, was read; — “ Since 
the publication in the ‘ Quarterly Journal of Science ’ for April, 1878, 
of my paper on Pedesis, or the so-called Brownian movement of micro- 
scopic particles, it has been suggested to me that soap would form a good 
critical substance for experiment in relation to this phenomenon. It 
is the opinion of Professor Barrett and some other physicists, that 
the movement is due to surface tension, whereas I believe that 
chemical and electromotive actions can alone explain the long- 
continued and extraordinary motions exhibited by minute particles 
of almost all substances under proper conditions. Soap considerably 
reduces the tension of water in which it is dissolved, without much 
affecting (as is said) its electric conductibility. If, then, pedesis 
be due to surface-tension, we should expect the motion to be killed 
or much lessened when soap is added to water. 
Having tried the experiment, I find that the result is of the 
* ‘ American Naturalist,’ vol. xii. p. 616. 
