446 



SCIIJJWGE. 



I Vol. IX., No 222 



THE UPRIGHT POSITION IN MAN. 



Dr. Guy Hindsdale of Philadelphia has car- 

 ried out a suggestion of Dr. Weir Mitchell's to a 

 very interesting conclusion (Amer. Journ. med. sc, 

 April, 1887). The suggestion consisted in the de- 

 sire to record accurately the swaying to and fro 

 and from side to side which every one feels him- 

 self involuntarily making when ti'ying to stand 

 perfectly still. Placing the heels and toes to- 

 gether, with the hands hanging from the sides, the 

 head erect, and the eyes directed to a fixed object, 

 a silk thread was attached to the forehead, passed 

 over a pulley, and was connected with a rod mov- 

 ing vertically and carrying an index. The index 

 recorded on the smoked surface of a revolving 

 drum. A fall of the line on the drum indicated 

 a forward movement of the head, aud an upward 

 line a backward movement. The lateral move- 

 ments of the head were similarly resolved into the 

 downward and upward tracings of a second in- 

 dex. A third curve recorded the respiration, and 

 a fourth marked seconds. 



Another method of recording the sway consists 

 in placing a flat piece of cardboard with a smoked 

 surface upon the subject's head, and have him 

 stand under an index free to move up and down 

 in a fixed line. The resulting tracing shows the 

 continuous movements which occurred. This 

 method is coarser than the other, but has practi- 

 cal points of interest for clinical purposes to 

 which it has already been applied. 



Without exception, all persons, including the 

 most healthy, swayed both forward and backward 

 and from side to side. The first movement is 

 generally the more extensive, and is, on the aver- 

 age, one inch, while the lateral sway averages 

 about three-quarters of an inch in normal adults. 

 The first movement is almost invariably forward, 

 then a counterbalancing movement backward vvith 

 a tendency towards the right. The rate of the 

 movement shows a rhythmical tendency of about 

 fourteen per minute, with a respiration of about 

 twenty-two per minute. The significance of this 

 rate has not yet been ascertained, and its con- 

 stancy suffers many deviations. 



An interesting observation is the common ten- 

 dency of falling forwards and towards the right, 

 which at once suggests all the problems of bi- 

 lateral asymmetry. The suggestion is borne out by 

 further trial ; for, while right-handed people al- 

 most invariably are inclined to tilt over to the 

 right, of twenty-two left-handed people, twelve 

 inclined towards the left. This agrees well with 

 the observations that the right arm is heavier and 

 larger than the left, and thus brings the centre of 

 gravity on the right side. That this is co-ordinated 

 with an increased development of the left brain is 



well made out, and receives its final confirmation 

 in the fact recorded by Flechsig, that more fibres 

 cross over in the pyramidal decussation from the 

 left brain to the right side than vice versa. 



That the eyes are used to correct these sway- 

 ings is well proved by the fact that, with the eyes 

 closed, the sway is increased by about fifty per 

 cent. So, also, absence of fixation of the eyes, 

 reading aloud, removal of the shoes and stock- 

 ings, materially increase the sway. 



Children sway absolutely moie than adults, 

 and there is greater equality in their case between 

 the antero-posterior and the lateral sway. Twenty- 

 five girls showed an average lateral sway of 1.06 

 inches, and an antero-posterior sway of 1.08 inches, 

 vi'hich was increased by about forty percent when 

 the eyes were closed. 



Thirty-nine blind persons gave an average lat- 

 eral deviation of 1.4 inches, and an antero-posterior 

 deviation of 1.7 inches, which is about the same 

 as that of seeing persons with closed eyes, thus 

 suggesting that the years of experience have been 

 of no avail in making the blind keep a truer 

 equilibrium than seeing persons momentarily de- 

 prived of sight. In deaf-mutes the lateral sway 

 was .93 of an inch, and the antero-posterior .85, 

 which averages became 1.18 and 1.31 with closed 

 eyes. All except two of these (all were right- 

 handed) swayed towards the right. (Incidentally 

 the observation of Professor James, that deaf- 

 mutes are less liable to dizziness than normal per- 

 sons, was confirmed.) 



From the clinical side, it was found that ether 

 exaggerates the normal sway considerably without 

 introducing other peculiarities. In locomotor 

 ataxia (characterized by unsteadiness and uncer- 

 tainty of the gait) the sway with the eyes open in 

 several cases was observed to vary from 3.25 to 

 3.75 inches on the antero-posterior line, and from 

 2.50 to 3.25 laterally. Six observations with the 

 eyes shut show a lateral sway of from 3 to 6 

 inches, and an antero-posterior sway of from 3 to 

 7 inches. A case of spastic paralysis showed the 

 deviations almost entirely in the antero-posterior 

 line, while in chorea the difference between the 

 deviations in the two directions is marked, and 

 both are exaggerated (lateral, 1.45 inches ; antero- 

 posterior, 2.35 inches). 



Dr. Hindsdale justly claims for these observa- 

 tions considerable suggestiveness for physiological 

 research and direct clinical utility. 



FLORIDA GEOLOGICAL SURVEY. 



For the first time in the history of the state, 



Florida has instituted a geological survey of its 



territory. The survey is not yet fully organized ; 



but a preliminary report of thirty-one pages, on 



