II
A V I A T I O NM E D I C I N E
THE JOURNAL OF

O&hl Publication of the Aero Medical Association
I

VOLUME 28

AUGUST, 1957

1

NUMBER 4

The Labyrinthine Posture Reflex (Righting
Reflex] in the Cat during Weightlessness
BY SIEGFRIEDJ. GERATHEWOHL,
PH.D., AND
MAJORHERBERT
D. STALLINGS,
USAF
inner ear known as otolith organs.
They are located in the utricle andthe saccule which are filmled with endolymph and contain the very specialized structure of macula and otoliths.
The otolith apparatus consists of aplaque of hair cells covered with amucus layer, which carries a large
number of very small particles of calcium carbonate, the so-called otoliths.
When the head is in an upright position, the macula of the utricle lies approximately in a horizontal plane, thatof the saccule in a vertical plane. The
planes of the two saecular maculas
form an angle opening forward anddownward.
The probable response of this organ
to weightlessness has been discussed
elsewhere.6+ Because of their physicalcharacteristics, the otoliths are "gravireceptors." They can move within themacula under the pull of their own
From the U. S. Air Force School ofweight, or in response to accelerative
Aviation Medicine, Randolph Air Force
forces and their inertial effects. This
Base, Texas.
Presented on May 8, 1957 at the 28th
movement bends or pulls, or shears
annual meeting of the Aero Medical Asthe epithelial hairs, thus distorting thesociation, Denver, Colora'do.

L T H O U G H it is generally accepted that linear accelerationis the physical stimulus for theotolith organ, its function during periods of increased and decreased gravity has not been ~ l a r i f i e d . ~In, ~ J1952,~
SlaterlG discussed the probable response of the otoliths to the weightlesscondition by drawing some tentative
conclusion from morphologic data andelectrophysiologic experiments madeby Adrian1 and Lowensteing, and by
Lowenstein and Raberts.lo The experiments in this report deal with theotolith functions of the cat. The findings are thought to throw some lighton the vestibular processes during subgravity and zero-gravity.
The means of sensing the effect ofgravity, which is actually a linear accelerative force, is provided by a setof mechanically affected organs of the345

POSTURE REFLEX--GERATHEWOI-IL AND STALLINGS
sensory cells and producing a stimulus.
Depending upon the position of thehead in the state of rest, the end
org'ans of the utricle and saccule areaffected in a certain way. The forcesof gravity and acceleration, caused byvoluntary and involuntary motion, arealso conveyed to the brain in theform of impulses traveling along thevestibular nerve. These impulses are
all of the same intensity but they vary
in frequency depending upon the direction and mode of acceleration.
The weight or movement of an otolith distorts the cell or cells closest toit. Minimal stimulation occurs whenthe maculas are horizontal and theotoliths rest on the hair cells ; maximal
stimulation is obtained when the otoliths hang from the cells or, with normal head position, when they arepushed upward. Now, in the weightless state, the otoliths are deprived of
their weight, too, and this should resultin a minute change of the cell structure. This then will bring forth analteration of the impulse rate of thevestibular nerve.
It is the opinion of many investigators that the fo.rce of gravity exerts
the most fundamental influence upon
our spatial orientation. ~,7,11,14 However, there is no need for the organism
to obtain a conscious knowledge of thedirection and amount of gravity. The
basic need is for a mechanism that
adapts the body automatically to theireffects. This is done by means of theso-called postural reflexes which arethought to serve to maintain or restore
the "normal" position and posture of
the body. This group of reflexes,
which includes the static and statoklnetic reflexes of the body, reveals that346

gravity has an essential effect upon
animal life. This effect is very difficult to assess but relatively easy todemonstrate.
One of the best-known reflexes ofthis sort is the postural righting reflexof the cat. Since the pioneer work of
Magnus, ~2'13 this reflex has beenstudied under various conditions. If
a cat is first held in any other thannormal position and then dropped, theanimal immediately turns into the normal posture so that it always lands on
its feet. A similar reaction occurs when
the cat, lying on its back with its head
held in an almost normal position, is
moved vertically downward. However,this reflex does not seem to function
when the cat is moved upward. Adrian's experiment on the cat has shownthat .changes in head position were associated with an alteration of the ilnpulse rate, which was caused either by
the act of tilting or by the angle oftilt as such. He found that pressure
toward the macula did not increase
the stimulus. This may account for thelack of postural righting reflex during
movement in the upward direction.
F r o m a practical viewpoint the question was asked how the righting reflexof the cat would work during subgravity and zero-gravity. Would thecat turn around when held upsided.own or would it stay in this position ?
Is there a time factor involved which
may indicate adjustment and adaptation? H o w will other c u e s - - f o r instance, visual orientation--affect thefunctioning of the reflex? The answers to these questions were sought
not only to satisfy ottr own curiosity,
AVIATION MEDICINEPOSTURE REFLEX--GERATHEWOHL AND STALLINGS
bu,t to clarify the role of the otolithorgan during weightlessness.
METHOD

Eight cats were used in the experiment; all were healthy young animals born in the School of Aviation
Medicine cat and dog kennels, andraised from three different litters.
Four of the kittens were about three
weeks old when used in the experiment; two of the kittens were about
eight weeks, and two young cats wereabout twelve weeks of age. The experiments were conducted as follows:
Each of the three sets of experimental animals first was taken into
the School of Aviation Medicine film
studio and placed on a table. The animals were then lifted up individuallyand held upside-down in a long
stretched position. They were released
unexpectedly and dropped from analtitude of about 20 inches. Wfien thethree-week-old kittens were employed,
the table was covered with a rubber
pad. In some of these experiments
the animals were blindfolded to exclude visual orientation. The behaviorof the animals was recorded on film.
This experiment was repeated several
times so that its result could be considered conclusive.
The animals were then taken into
the air and exposed to short periods ofweightlessness.
Virtual weightlessness, or a state of reduced gravity,
was produced by flying a jet type aircraft (T-33 or F-94) along a Keplerian trajectory. 4'5 The ascent to
20,000 feet was made at a rate ofclimb of 2,000 feet per minute. T'hecabin pressure at that altitude wasabout 9.5 psi, which is equivalent of
Aucus~ 1957

an altitude of approximately 12,000
feet. The pilot of the craft ( H . D . S . )flew the ascending arc of the parabola at full throttle and the descending part with about 75 per cent rpm
in order to obtain weightlessness forabout 25 to 35 seconds.
A.bsolute
weightlessness or zero-gravity occurred for only a few seconds during
each of t:hese maneuvers due to thesmall accelerative forces present. Theseunavoidable accelerations were of an
estimated magnitude of about 0.03 to
0.05 G. The weightless state was indicated and controlled by the conventional G-meter installed in all fighter typeaircraft. Before entering into the parabo.la and during recovery from thedive, accelerations .of 1.25 G were not
to be exceeded because it was observed
du'ring the first flight that the catswere extremely sensitive to an increaseof acceleration. Five or six parabolas
were performed during each experimental flight.
The small kittens were taken alongin pairs and kept in a container until
the working altitude was reached. The
older animals were used one at a timeand carried on the a r m of the experimenter in the aircraft (Fig. 1). The
cats were turned upside-down and released after periods of 1, 51 10, 15, 20
and 25 seconds after entering theweightless state. The behavior of theanimals was studied under 'both blindfold and nonblindfold conditions andrecorded on film.
Motion pictures were made using
a 16 ram. Filmo camera, model 70 H,
with a 13 mm. lens, f ~ 1.5, and afilm speed of 24 frames per second.
Kodachrome film with a K o d a k No.
83 filter, and one Eastman Panchro347

POSTURE

REFLEX--GERATHEWOI-'fL AND STALLINGS

Fig. 1. Photograph ofcat before the experimentin the T-33 aircraft.

9 [8Fig. 2. Prompt ,righting
reflex of cat immediately
upon entering the weightlesscondition.

Fig. 3. Delayed reflex:
the cat turns slowly after acertain delay.

AVIATION MFA}ICINEPOSTURE REFLEX--GERATHEWOFITL AND STALLINGS

Fig. 4. Postural righting
reflex fails completely; thecat floats in an inverted
position.

AUGUST, 1957

Fig. 5. Disturbed reflex
associated with slight tumbling.

Fig. 6. No righting reflex.
The animal floats
slowly upwards due to acceleration in this direction(so-called "negative G").

349

POSTURE REFLEX--GERATHEWOFIL AND STALLINGS
matic black-and-white film for illustration purposes, was used. The camera was attached to the airframe on
top of the instrument panel between
front and rear seat of the T-33 aircraft, and focused at a distance ofabout 100 can. In the F-94 aircraft
the camera was installed below therear panel and focused slightly upward
at a distance of about 75 cm. It was
switched on shortly before each parabola and stopped at the end of it. Some
illustrations of the results are given
in Figures 2, 3, 4, 5 and 6. Unfortunately, the animal is only partly visible
in these pictures because o.f the small
field size and the limited elevation of
the camera.
The evaluation of the films consisted of an analysis of the moving
pictures as well as the stills by describing briefly the behavior of theanimals with regard to. promptness ordelay .of the righting reflex under theconditions of reduced gravity. T o thisend, the films were run at normal
speed and additional .checks of eachscene of exposure of .the cat weremade by looking at each individual
frame when the. film was moved byhand. The observations were thentabulated; the reflex response was related to the length of time spent in
the weightless condition. Thus, somenumerical results were obtained whichmust be considered for what they areworth.
RESULTS

Even before the experiments werestarted it was observed that the fouryounger animals fell straight downwhen they were dropped on the
ground. W e found that the postural
350

righting reflex of the cat develops during the fourth tilt sixth week after
birth. Hence, in describing the behavior of ou'r animals we must distinguish between (1) the three-weekold kittens whose postural righting reflex was not developed, and (2) theeight and twelve-week-old ones whosereflex was well established. W e cansummarize the behavior of the firstgroup very briefly.
The motion pictures of the younger
kittens made on the ground and in
the air show very clearly that in nota single case did the animals turnaround a f t e r they were released. They
fell or floated in an inverted position
under normal gravitational and undersubgravitational conditions, respectively. Since the righting reflex was notdeveloped, blindfolding was meaningless, of course. The responses of thisgroup of animals were not t~bu'Iated
due to the uniformity of behavior.
The behavior of the older animals,on the other hand, showed considerable differences under the various experinaental conditions. On the ground,
the reflex functioned promptly and sounanimously that the results were nottabulated either. The responses of thefour older animals upon exposure toweightlessness, however, were tabulated and are given in Tables I and I1.
In the first table, the behavior of thetwo eight-week-old kittens is described.
As can be seen in this table, the animals turned .back into their normal
posture at the first exposure to weightlessness. This reflex seems to be delayed or disturbed in the later trials.
Table I I contains the description of
the two oldest animals. Again, the general impression is that the cats turn
AVIATION MEDICINEPOSTURE REFLEX--GERATHEWOtIL A N D STALLINGST A B L E I. B E H A V I O R O F T H E A N I M A L W H E N E X P O S E D I N A N U P S I D E - D O W N P O S I T I O N
TO S H O R T P E R I O D S O F W E I G H T L E S S N E S S A T V A R I O U S I N T E R V A L S A F T E R
THE SUBGRAVITY STATE BEGINS

AnimalGrey kitten A

Parabola : No. of Exposure

Condition

Time

1

1
2
3

Eyes open
Eyes open
Eyes open

Immed.
510

2

1

Eyes open
Normalposition3

1
2

Eyes open
Eyes open

3
4
1
2
3
4
5 (?)
1
2
3

Eyes open
Eyes open
Hood
Hood
Eyes open
Eyes open
Eyes open
Hood
Hood
Hood

1
2
1

Eyes open
Eyes open
Hood

4

5

3rey kitten B

1
2

AUGUST~ 1957

Immed.
5
Immed.

2

Hood

3

1

Eyes open

5

4

2
3
1
2

Eyes open
Eyes open
Hood
Hood

10
15
Immed.
5

5

3
4
1
2

Hood
Eyes open
Hood
Hood

10
20
5
10

6

1
2

Eyes open
Eyes open

10
15

into the normal position during thefirst exposures; but that the reflex
is delayed or does not occur at all
toward the end of the experiments.
To obtain a clearer picture of the
uccurrence and mode of the righting
reflex, particularly in regard to thetime factor, the responses of the four
older animals were tabulated (TableI I I ) . In this table, the beginning of
the exposu're of the cat t.o be weightless condition is indicated by timevalues from one to twenty-five seconds, which are approximations because of the awkward situations whichsometimes occurred when the animal

Response

Prompt righting reflex
Delayed righting reflex
No righting but tumbling due towild motor response
Immed. Floating upward and delayed turninj
upside-down due to accelerations
a c t i n g in t h e opposite d i r e c t i o n(negative g's).
10
No righting
15
No righting and floating upsidedown for a few seconds
20
No righting reflex
25
No righting reflex
10
No righting reflex
15
No righting reflex
20
No righting but tumbling25
No righting but floating
30 (?) No righting, floating upward5
No righting, floating upward
10
Righting, tumbling
15
No righting; floating upward andtumbling

10

Righting reflex somewhat delayed
No righting, floating upward
Righting, floating upward, turning
again upside-down
No righting, floats upward and downward upside-down
R i g h t i n g a n d t u r n i n g a b o u t longitudinM axis
Delayed righting
Righting reflex
Righting
No righting but tumbling into vertical, then normal
Delayed reflex
Floats downward, then delayed reflex
Floats upward, tumbling
Floats upward, tumbling and turningin normal position
Righting
Delayed righting and tumblingrefused to be released or clung to af.oothold in the cockpit. In column 2,
the given number of parabolas varies
from five to six for the respective
animal. Column 3 is subdivided in
responses obtained under .blindfold
and nonblindfold conditions; the firstnumber being smaller because the animal succeeded in stripping off the hoodon several occasions.
An inspection of Table I I I confirms
the observations made in the aircraft
and the general impression obtained
from Tables I and II. Upon release
immediately, or not later than abou,t
5 seconds, the animal turned into the351

POSTURE REFLEX--GERATHEWOHL AND STALLINGS
TABLE

II.

BEHAVIOROF

WEIGHTLESSNESSINTERVALSTHE

ANIMALWHEN

IN AN UPSIDE-DOWN
AFTER

EXPOSEDTOPOSITION

THE SUBGRAVITYSHORTPERIODSOFAT VARIOUS

STATE BEGINS

AnimalParabola

No. of ExposureTime

Response

Black and white cat

1

1
2
1
2

Hood
Hood
Hood
Hood

5
10
5
10

3
1

Hood
Eyes open

20
10

1
2
1
2
3
4
5
1
2

Hood
Hood
Hood
Hood
Hood
Hood
Hood
Hood
Hood

P r o m p t righting reflex
Prompt rightjmg reflex
Prompt righting reflex
N o r m a l position, t u r n i n g upsidedown due to acceleration in opposite
direction (negative g's)
Delayed righting reflex and turning
No turning, floating upward, grasp~
top string
Righting reflex
Righting reflex
Righting reflex
Righting reflex
Floating, no reflex
No righting reflex
No righting reflex
Righting reflex
Floating upward, no turning, grasp~
top string

2

White cat

ConditionlEyes open

5

1
2
3
1
2
3

Eyes open
Eyes open
Eyes open
Eyes open
Eyes open
Eyes open

5
10
15
5
10
15

1
2
3
1
2
3

Eyes open
Eyes open
Eyes open
Eyes open
Eyes open
Eyes open

5
10
15
Immed.
5
15

normal position eleven times when
visual cues were available, and tentimes when they were blindfolded.
After a latency of about 15 or 20 seconds, the righting reflex occurred or
failed about the same number of times
when tile cats were not blindfolded.
W'hen the hood was used, the sameratio of responses was already obtained after 10 seconds. F r o m thistime on the reflex failed in five cases.
With eyes open no righting response
was observed among the few cases exposed a f t e r a period of twenty-fiveseconds. By and large, we found thatthe postural righting reflex ceased tofunction after a stay of more thantwenty seconds in the weightless state;
and that visual .cues did not seem toaffect the reflex to a marked degree.
352

Immed.
5
Immed.
510
15
20
Immed.
5

Floating upward, delayed rightinl~
reflexPrompt righting reflex
P r o m p t righting reflex
P r o m p t righting reflex
Righting reflex
Floating upward, no righting
Floating upward, tumbling but nc
righting reflex
Floating upward, no righting reflex
Floating upward, no righting reflex
Floating briefly, no righting reflex
Righting reflex
Delayed righting reflex
Righting reflex, slightly delayed

DISCUSSION

Magnus 12 has demonstrated that
normal animals acqu~ire and maintainposture by various static and statokinetic reactions. In our experiments,
both types of reflexes will also be
activated because the cat normally does
not like to lie on its ~back, nor to be
moved irt this position in a verticaldirection. W h e n a cat is held backdownward and then allowed to fall,
the otollth reflex acting upon the neckmuscles turns the head of the animal
rapidly into its normal position. The
contraction of the neck muscles, whichrotate the head, activates the myotatic
neck reflexes which affect the musclesof the body by turning the thorax andthen the pelvis into the normal posture.
This reaction can be seen in pictures
Av~TION Mv_~ICaNE

POSTURE REFLEX--GERATI-IEWOI~L AND STALLINGS
TABLE

III.

OCCURRENCE
THE

OF
SUB-

RIGHTINGAND

REFLEX

ZERO-GRAVITYAT

VARIOUSSTATESINTERVALS

AFTER

BEGIN

B e g i n n i n g of E x p o s u r e of A n i m a l in Seconds
W i t h E y e s OpenAnimalParabola

1510Grey kitten A

1
2
3
4
5

+
x*

•

--

Grey kitten

1
2

B

3

-F

--

+

+

4
5
6
Black a n d white c a t

15

20

+

-I-

Wit
25

++x+.

;++

5
6

2
3

+
-t- --

+
--

+

_+

+

Righting reflex (-l-)

6

2

3

1

Delayed reflex (4-)

1

2

1

1

3

5

2

4
5

25

-t-

21
3

1

i [ 20•4White c a t

Hood

5 I~

+

+
-t-

1

No r i g h t i n g reflex ( - - )

1

q-

--

7

3

1
2

2

2

I 4

3

3

2

* A n i m a l w a s held in n o r m a l position a n d a n acceleration opposite to the direction a n d stronger t h a n t h e force ofgravity w a s employed.

of a promptly functioning righting reflex (Fig. 2).
Although we have enough evidence
to assume that the postural righting reflex was generally produced by anotolith response, this reflex can be
reinforced by exteroceptic or visceralstimulation. Because the animal was
symmetrically supported in our experiments, reinforcement of the postural righting reflex by the so-.called"body righting reflex" can be neglected. However, there is the possibility of a .certain reinforcement throughthe loss of touch and grip pressureduring the release of the animal. This
may account for some of the reflex
actior~s in an advanced state of weightlessness.
AUGUST, 1957

Because visual ,cues play a prominent role for the orientation of thecat, the occurrence of the so-called".opticM righting reflex" was controlled
by means of the hood. This reflex was
observed in those cases in which r
animal turned or stretched itself inorder to grasp the top or the side of
the canopy. There is some evidence
from Ta,ble I I I that blindfolding
changed'the reflex pattern but slightly.
Natural.ly, we cannot expect therighting reflex to occur hero.re it has
been developed. A f t e r this was accomplished, the reflex should fail only
if there is a complete lack of stimulation. During the transition from thenormal state of gravity into st~bgravity, the gravireceptors are stimulated.
353

POSTURE REFLEX--GERATHEWOI-IL AND STALLINGSThis may have cau'sed the righting
response of the animal when released
immediately upon entering the weightless state. On the other hand, if theanimal was in this state for a certain
period of time and was then released,
the reflex was delayed or failed. It
should have failed completely if true
weightlessness were obtained. Hence,
it seems that the righting reactions observed toward the end of the parabola
were caused by the slight changes inacceleration, which unfortunately occurred during most of our weightlessperiods.
The response pattern obtained in our
experiments must be attributed to thechanged stimulus pattern of discrepant
gravitational, visuM and tactile cues
which caused spatial disorientation.
This may 'be the main reason why the
animal became so confused and fought
against being exposed to the weightless condition, and why the posturalreflex was disturbed. These experiments also show that the otoliths mostprobably are not stimulated by acceleration as such, but by the changes ofacceleration. In the weightless condition of our experiment the animal issubjected to the constant accelerationof gravity, but this force does not seemto activate the postural righting reflex. Physiologically, this is understandable ,because it is the initialchange of the physical state of theotoliths that ,produces an inertial effectto elicit the sensory stimulus indicating the alteration of the physical condition: Thereafter, the otoliths "movealong" with the maculae, and only thealteration of this condition by deceleration brings forth the inertial effects
354that will stimulate the gravireceptors
again.
EI.ow powerful this stimulation canbe was demonstrated by the two exposures of the cats tO accelerations
producing centrifugal forces different
from the direction and stronger than
the force of gravity. The black andwhite cat tended to turn in the apparent direction of gravity, but the reflex was delayed and incomplete due
to ,the almost normal position of ,thehead. The grey kitten turned immediately from the normal position upward and landed in an inverted position at the top of the canopy. In thiscase, the physiologic condition wasvery similar to that when the kitten
was dropped in the upside-down position. Because the Posture of thehead was inverted from one condition
to the other, the inertial effect on theotoliths is the same when the directionof acceleration is reversed. The inverted righting response occurred although visual cues were available.
SUM,MARY AND CONCLUSIONS

Experiments on the postural righting reflex were made using (1) fouryoung kittens before the reflex wasdeveloped, and (2) four older kittens
with the reflex well established. On
the ground, the animals were dropped
in upside-down position from an altitude of abou't twenty inches, and laterin the air exposed to period,s of about
twenty to thirty seconds of practicalweightlessness. The reflex was studied in T-33 and F-94 aircraft underboth blindfold and non-blindfold conditions. The behavior of the cats wasrecorded on 16 ram. film.
Av~T~o~ MF.mC~N~

P O S T U R E REFLEX--GERATHEWOI-IL AND STALL]NGSThe motion pictures were evaluatedby repeatedly watching the film, andby an analysis of the individual
frames. On the ground, the younger
animals fell straight down; the older
ones turned upright immediately after
release without exception. In the air,the younger kittens floated upsidedown du'ring weightlessness; the older
ones turned upright at the beginningof the weightless state, but their reflex failed after several exposures. By
and large, it was observed that thepostural righting reflex of the catceased to function a f t e r a period of
about twenty seconds of practicalweightlessness; .and that the available
visuM cues did not affect essentiallythe reflex pattern.
REFERENCES

1. ADRIAI,~,E. D. : Discharges from vestibular receptors in the cat. J. Physiol., 101:389, 1943.
2. CLARK,B., and GRAYBIEL,A. : Disorientation: A cause of pilot error. USN
Sch. ,4viat. Med., Joint Proi. Rpt.
No. NM 001 100.9, March 1955.
3. GAUER,O., and HABER,H. : Man undergravity-free conditions. 'In Ger~a~Aviation Medicine, World War II,
U. S. Government Printing Office,Washington: Department of the Air
Force, 1951, pp. 641-644.

4. GERATItEWOHL, S. J., STRUGHOLD, H.,
and STALLINGS, H. D. : Sensomotor

performance during weightlessness:
Eye-hand coordination. J. Av. Med.,
28:7, 1957.

5. GERATttEWOHL, S. J. : Personal experiences during short periods of weight-

lessness reported by sixteen subjects.
Astronautica Acta, 4:204, 1956.
6. GOUaF-ROT,L. : Loi de Weber- Fechner
et variations de la pesanteur apparonto. Med. Aeronaut., 8:119, 1953.
7. GRAYBIEL, A. : The oculogravic illu'sion. USN. Sch. Avi~t. Med., Proj.
No. NM 059.01.27, December, 1951.
8. HABER, H., and GERATHEWOHL, S. J. :Physics and psychophysics of weightlessness. J. Av. Med., 22:180, 1951.
9. LOWENST~IN,O. : Symposia of the Society for Experimental Biology(Brit.), No. IV:N, 1950.
10. L0WENSTEIN, O., and ROBERTS, T. D.
M. : The equilibrium function of ~heotolith organs of Thornback Ray(Raja clavate). J. Physiol., 110:392,
1949.
11. MACH, E.:
Physikalische Versucheueber den Gleichgewiehtssinn des
Menschen. Sitzgsber. d. Kaiserl.
Akad. d. Wissen.wh., 46:124, 1873.
12. MAGNUS,R.: Kaerperstdlu~g. Berlin:
Springer, 1924.
13. MAGNUS, R. : Studies in the physiology of posture. Lancet, 211:531, 1926.
I4. MANN, C. W. : Studies in space perception. USN Sch. Avlat. Med.
Rep. No. t8, 1950.
15. SIMONS, D. G. : Review of biologicaleffects of subgravity and weightlessness. Jet Propulsion, 25:209 May,
1955.
16. SEATER, A. E. : Sensory perception of
the weightless condition. Annual Rep.
Brit. Interplanet. Soc. 1952, pp. 342348.

Importance of Aircraft Sanitation
Domestic airlines today are spending more money to feed their passengers than they spem not m a n y years ago to fly them. Airline catering has
become a specialized trade. In compliance with good sanitation standards,
galley equipment is designed to facilitate cleaning--corners are rounded,seams are tight, and parts are removable. Although the p r i m a r y aim ofsanitation is to prevent the spread of communicable disease, an immediate
benefit in air travel is that protection of the pilots' health enhances safety.
A pilot suffering from severe nausea, vomiting, headache, diarrhea, o r
cramps would be a hazard to the safety of his plane, its passengers, andits crew.--HEALTH ALOFT: P h y s i d a n ' s Bulletin, October, 1956.
AUGUST, 1957355