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POPULAR SCIENCE REVIEW. 
stationary till “ the striking distance ” between the poles agam becomes too 
great, when the above described action is again repeated ; but beyond this, 
when the current between the carbons begins to weaken, an oscillatino- action 
commences, and as small portions of air, in consequence, escape from the 
tube, the upper carbon supporting-rod is gTadually lowered, so that it will Idc 
seen the action is perfectly sympathetic, for as the carbon bums away, they 
are gradually brought nearer to each other by this compensating power, and 
if a piece of either of the carbons break off, so that “ the striking distance ” 
by such an accident becomes too great, the poles are immediately brought 
into contact and the light reinstated. In place of the Tilley blowpipe 
arrangement, a simple air-cushion and springs may be employed, but Air. 
Highley thought the first to be less hable to disarrangement through changes 
of temperature. There are other points of detail, which, however, are not 
necessary for a comprehension of the principle of action of this electric 
regulator. 
Structure of the Thumb in Ai^es. — This subject, which has had such an 
important bearing upon the semi-theological discussion as- to man’s place in 
nature, has lately received the attention of that distinguished brain-anatomist, ^ 
M. Gratiolet. This savan declares that according to his dissection the differ- 
ences between the hands of man and apes are far more striking than has 
been supposed. In the latter the thumb is moved towards the palm by an 
obhque division of the tendon of the common flexor muscle of the fingers ; 
hence it is drawn in during all movements of flexion on the part of the 
fingers, and has no intrinsic or special j)ower of motion. The same type of 
structure is observed in the gorilla and chimpanzee ; but the small tendon 
which should move the thumb, is reduced in these species to a mere tendinous 
thread, which has no action, for at its origin it is lost in the synovial folds of 
the flexor tendons of the other digits, and it does not terminate in a muscular 
fasciculus ; the thumb therefore has its typical power very much diminished 
in these animals. In none of them is there the famtest trace of that power- 
ful and uidependent muscle which moves the human thumb, and, so far from 
being of a complete form, this phalanx (so characteristic of the human hand) 
appears in the liighest of these Apes — the Orangs — to have a tendency to 
atrophy. — Vide a paper read before the French Academy, Aug-ust 17. 
The ^^Spontaneous Generation^^ Controversy.— Among the latest disputants 
of M. Pouchet’s favourite doctrine, we may mention the name of M. Coste, 
the celebrated embryologist, and advocate of oyster culture. He insinuates 
that the microzoa (infusoria), which M. Pouchet supposes to have been 
developed spontaneously, were derived from external sources, and travelled 
through the filters which were employed as barriers ; but M. Pouchet makes 
a very apt reply to the effect that, according to M. Balbiani’s measurements, 
the diameters of the cihated infusoria which he produced are far greater 
than those of the porosities observed in filter-paper. He admits that a few 
infusoria pass through, but denies that any of these are ciliated. The micro- 
zoa which he has produced arise from spontaneous eggs which are developed ; 
in decomposing matter. The spontaneous ovum is clear, transparent, and ^ 
ZOOLOGY AND COAIPAEATIYE ANATOAIY. 
I 
