120 



SCIENCE. 



[N. S. Vol. I. No. 5. 



and the phrenic nuclei does not inhibit the 

 the phrenic cells on the side of the section. 

 It follows that two hemisections, com- 

 pletely separating the cord fi-om the bulb, 

 do not inhibit the diaphragmatic respiration 

 on their respective sides. The phrenic cells 

 often send out no respiratory impulses af- 

 ter such a section because they receive none 

 from the bulb. The phrenic cells cannot 

 themselves originate respiratory impulses. 

 Hence, the respiratory impulse does not 

 arise in the spinal cord. 

 Demonstration — Hemisections of the Spinal Cord 

 above the Phrenic Nuclei do not inhibit Tho- 

 racic Respiration. W. T. Poeter. 

 Acuteness of Vision in St. Louis Public School 



Children. W. T. Porter. 

 The Weight of Dark-haired and Fair-haired 



Girls. W. T. Porter. 

 Exhibition of Some New Forms of Galvanometers 

 Suitable for Physiological Use, With Remarks 

 Upon the Same. Prof. H. A. Eowland, at 

 the Physical Laboratory of Johns Hop- 

 kins University. 



Professor Rowland exhibited two new 

 forms of high resistance galvanometers. 

 One was a modification of the Thompson 

 galvanometer, but less expensive in con- 

 struction, and possessed a greater delicacy ; 

 the other was a modification of the Dar- 

 sonval galvanometer, and was arranged 

 with the observing telescope on a convenient 

 wall support. It was shown that thej^ were 

 well adapted for laboratory use in Physio- 

 logical work. 



Demonstration of an Apparatus for the Plethys- 

 mographic Study of Odors, toith Report of 

 Results. T.E. Shields. (Introduced by 

 W. H. Howell.) 



Mr. Shields exhibited his apparatus, and 

 gave the following account of its use : 



1 . It consists of a device for holding the 

 arm firmly in place in the Plethysmograph. 

 Two hard rubber clasps, one fitting the wrist 

 and the other the arm above the elbow, are 

 rigidly connected by two metal rods. The 



latter of the clasps fits against the Ple- 

 thysmogTapli under the rubber membrane, 

 where it is held in place by two other rigidly 

 connected clasps, one against it outside the 

 rubber membrane, and the other against 

 the flange of the PlethysmogTaph . 



2. A device for separating the pulse and 

 vaso-motor curves. A short ivlde tube leads 

 fi'om the Plethysmograph to a vertical glass 

 cylinder in which the water level can be 

 made to register the pressure on the arm. 

 Over the water is an ah- cushion connected 

 mth the tambour by a small tube through 

 a jjistou movable in the cj^linder. The 

 motion of the piston controls the size and 

 pressure of the ail- cushion. The lever of 

 the tambour is made to move the point of 

 an independently supported pen. A long 

 narrotv tube leading from the Plethys- 

 mograph dips into a test-tube of water 

 swung from a delicate spiral spring. 

 (Method described by Professor H. P. 

 Bowditch.) A vertical thread from the 

 bottom of the test-tube passes under a pulley, 

 thence horizontally over a second pulley, 

 and is held taut bj' a small weight. On its 

 horizontal part is fastened a thin aluminum 

 plate capable of holding a glass pen at right 

 angle to the thread. The bulb of the pen 

 is independentlj' suspended by a vertical 

 thread. The pendular motion due to the 

 latter in the direction of the horizontal 

 thread is so adjusted as to neutralize tlie 

 curvilinear motion of the pen arising fi-om 

 the sag in the horizontal thread. The point 

 of the pen may thus be made to describe a 

 straight horizontal line. The resistance to 

 the motion of the water in the narrow tube 

 is sufficient to destroj' all but vaso-motor 

 effects ; pulse effects are, in consequence, 

 only felt through the ivide tube. 



The odors are contained in a series of 

 bottles. The turning of a stopcock, which 

 sends the constant current of air through 

 any particular odor-bottle, at the same time, 

 by an electrical arrangement, marks the in- 



