--_St. Louis Med. Jour._
* * * * *
A NEW APPARATUS FOR THE STUDY OF CARDIAC DRUGS.
By WILLIAM GILMAN THOMPSON, M.D., New York.
The apparatus was devised by Mr. R.D. Gray (the inventor of the
ingenious "vest camera" and other photographic improvements) and by
myself. I described what was required and suggested various
modifications and improvements, but the mechanical details were worked
out exclusively by him. To test the rapidity of the camera, we
photographed a "horse-timer" clock, with a dial marking quarter
seconds, and succeeded in taking five distinct photographs in half a
second with _one_ lens, which has never before been accomplished
excepting by Professor Marey,[1] at the College de France, who has
taken successive views of flying birds, falling balls, etc., with one
lens at a very rapid rate. His camera was unknown to me until after
mine was constructed, so that as a success in photography alone the
work is interesting.
[Footnote 1: La Methode Graphique (Supplement), Paris, 1885.]
The camera consists of a circular brass box, 51/2 inches in diameter and
11/4 inches deep, containing a circular vulcanite shutter with two
apertures, behind which is placed a circular dry plate. Both plate and
shutter are revolved in opposite directions to each other by a simple
arrangement of four cogged wheels moved by a single crank.
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