JANUAEY22, 1397.] 



SCIENCE. 



131 



tempt to go to sleep a gradual increase in 

 volume took place, the unconsciousness of 

 :sleep appearing at some point during this 

 increase. The volume reached its maxi- 

 mum within one or two hours after the be- 

 ginning of sleep, and then for an hour or 

 two remained practically constant. Fol- 

 lowing upon this there appeared a gradual 

 •constriction, which at first was very grad- 

 ual, but increased more rapidly during the 

 last half or three-quarters of an hour of 

 sleep, and brought the volume curve at the 

 time of awakening nearly or quite to the 

 point shown at the beginning of sleep. 

 The curves exhibited also throughout the 

 sleeping period long periodic waves of con- 

 striction and expansion, lasting for an hour 

 or more, and numerous shorter rapid con- 

 strictions and expansions, which were con- 

 nected with the movements of the sleeping 

 subject or with external stimuli such as 

 noises in the street. 



Upon the assumption that the increased 

 volume was owing to a vascular dilatation, 

 particularly in the skin, the author pointed 

 •out that upon the accepted view of the 

 regulation of blood supply in the brain, the 

 volume of circulation and the pressure with- 

 in this organ during sleep must stand in 

 reciprocal relations to the volume changes 

 exhibited by the limbs, that is, during the 

 period of sleep the blood supply to the 

 brain and intracerebral pressure gradually 

 diminish to a minimum which is reached 

 within the first one or two hours; this con- 

 dition remains practically constant for the 

 following hour or two, and is then succeeded 

 by a gradual increase in blood flow and in- 

 tracerebral pressure, which may be said to 

 reach the normal condition at the time of 

 awakening. The author explained the vas- 

 cular changes by a fatigue and subsequent 

 resumption of tone in the vaso-motor cen- 

 ter, especially in that part controlling the 

 skin circulation. He pointed out the want 

 of parallelism between the curves of inten- 



sity of sleep and the curves showing the 

 vascular changes, and developed a theory 

 of sleep which referred the immediate cause 

 of sleep and of spontaneous awakening to 

 the conditions of blood supply and pressure 

 in the brain, which are indirectly controlled 

 by the state of the vaso-motor center. 



Tlie relation between height, weight and age in 

 growing children. H. P. Bowditch. 

 Prof. Bowditch showed curves derived 

 from his own observations on Boston school 

 children, and those of Dr. Porter on St. 

 Louis children, showing that the relation 

 between height and weight varies with the 

 age in such a way that older children are 

 heavier in proportion to their height than 

 younger children. 



On the contraction of the stomach produced by 

 direct stimulation and by stimidation of the 

 vagiu'ith the faradic ciirrent. S. J. Meltzer. 

 1. Bipolar faradic stimulation with a 

 current strong enough to produce a maxi- 

 mal contraction when applied to the serosa 

 usually fails to produce any local or peri- 

 staltic contraction of the muscularis of the 

 stomach, when applied to the mucous mem- 

 brane of any part of the stomach. 2. When 

 the faradic stimulus is applied to the serosa 

 the effect varies according to the part of 

 the stomach which is stimulated. As re- 

 gards contractility, the stomach possesses 

 a negative and a positive pole ; the extreme 

 end of the fundus does not even with very 

 strong stimuli contract, while the pyloric 

 end responds to a moderate stimulus with 

 a strong contraction. The parts lying be- 

 tween the poles show a gradual transition 

 from one extreme into the other ; the 

 further from the left end of the stomach, 

 the walls contract more readily and more 

 strongly. 3. Stimulation of the pneumo- 

 gastric nerves causes a distinct contraction, 

 which is strongest after the cessation of 

 the stimulation. This contraction is also 



