318 
POPULAR SCIENCE REYIEW. 
was repeated on the eye of another person, the same day, with similar 
results. After this he made numerous experiments with magnets of dif- 
ferent forms and powers (though not at any time with very large ones) 
applied to various parts of the body, and thought he observed a definite set of 
symptoms arise after every application in the same manner to a given part, 
provided sufficient time had elapsed between the applications. The author 
then details several curious experiments, which some of our readers would 
do well to repeat. 
Dust and the Germ Theory of Disease. — The Scientific American reports 
that the New York Officers of Health have been examining the dust of the 
air in the American city. Over one hundred specimens of the particles 
floating in the air and falling as dust were collected on plates of glass, and 
were examined under the microscope. The proportions of the different in- 
gredients varied, but the same substances were found in all the specimens. 
The composition of the matter subjected to the microscope was as follows : — 
“ The dust of the streets, in its finer or coarser particles, according to the 
height at which it had been collected, with a large proportion of organic 
elements ; particles of sand, of quartz, and felspar ; of carbon, from coal- 
dust, and lampblack ; fibres of wool and cotton of various tints ; epidermic 
scales ; granules of starch, of wheat, mainly the tissues of plants ; the epi- 
dermic tissue, recognised by the stomata, or breathing pores ; vegetable 
ducts and fibres, with spiral markings ; vegetable hairs or down, either 
single or in tufts of four or eight, and of great variety, and three distinct 
kinds of pollens. Fungi were abundant, from mere micrococcus granules 
to filaments of mould. When water was added to a portion of dust, from 
whatever source, and exposed in a test-tube to sunlight or heat for a few 
hours, vibriones and bacteria made their appearance.” 
Diseases of Lucifer- Match Makers. — At the meeting of the Academy of 
Sciences of Paris on March 21 M. Jouglet read a paper on the diseases of 
the above class. He states that these people suffer from a peculiar series 
of diseases of the reproductive system. 
Functions of the Nerve-Centres in the Frog. — The Academy reports that 
Professor F. Goltz, of Konigsberg, has been continuing his observations on 
the different nerve-centres of the frog. After removing the cerebrum with 
as little effusion of blood as possible, the frog remained on the table in 
exactly the position of a sound animal, and without any indication of the 
injury it had sustained ; but, of its own accord, would never change the 
position once assumed. If pinched or pressed, it would turn itself round, 
or remove itself by a leap from the 'external pressure, but would then 
remain equally unchangeable in its new attitude. 
Influence of the Serving -Machine on Health. — Dr. Decaisne’s report on this 
subject to the French Academy (May 16) is somewhat reassuring. Con- 
cerning the influence of the machine on the nervous system, he does not 
consider the noise of the machine injurious in any way, as has been alleged; 
for it is acknowledged by all workwomen that, although at first the vibration 
of the machine occasions them some inconvenience, they soon become accus- 
tomed to it, and also that it has no effect whatever on their health. Dr. 
Decaisne is of opinion that the sewing-machine, as worked by women, when 
employed within reasonable limits, is not more injurious for the health than 
