An Apology 
“T think Luciani ts right in regarding 
yawning as an expression of drowsiness, 
but I believe also that too much 
emphasis has been placed on the factor 
of ventilation of the lungs. Asa matter 
of fact, if one yawns widely, there is a 
total cessation of the movements of the 
thorax and diaphragm during the period 
when the mouth is most widely open. 
This I attribute to the stimulation of 
the endings of the glossopharyngeal 
nerve in the pharynx and uvula by the 
stretching of these portions of the 
alimentary tract at that time. It is well 
known that stimulation of the glosso- 
pharyngeal nerve will stop all respira- 
tory movements immediately. Such 
a cessation normally occurs during 
swallowing. At the moment anything 
touches the uvula, respiration ceases 
immediately. One can feel the stretch- 
ing of the pillars of the fauces and of 
the pharynx and uvula, or, more 
correctly, the part of the soft palate 
immediately to each side of the uvula, 
when the mouth is widely open in 
yawning.”’ 
Not only is yawning a very primi- 
tive adaption (if, indeed, it be an adapta- 
tion) but it appears to go back to a 
remote stage of evolution, perhaps far 
below the age of mammals. On this 
point Dr. Pike remarks: 
“In thinking over the matter super- 
ficially it appears that the primitive 
respiratory neuro-muscular mechanism 
is the part particularly concerned. In 
for Yawning 449 
fishes, the respiratory system involves 
the musculature of the mouth and 
possibly of the pharynx, and the, 
nerves concerned are the fifth, seventh, 
ninth, tenth and twelfth cranial. The 
diaphragm and the phrenic nerve have 
not yet made their appearance, and 
the intercostal nerves and muscles are 
not concerned in the respiratory move- 
ments. That is what I mean by the 
primitive neuro-muscular respiratory 
mechanism. The muscles of the face 
and pharynx are involved in yawning, 
and the fifth, ninth, tenth and twelfth 
cranial nerves are also involved. I 
do not know where in the animal scale 
yawning first appears, but I should 
imagine that we might expect it in all 
the mammals, and possibly in some of 
the poikilothermal forms. It seems to 
be present in birds. In some respects, 
it approaches the type of respiration 
that is seen in cases of approaching 
death. In such circumstances, we 
have again the participation of the 
primitive neuro-muscular respiratory 
mechanism. The mouth is opened 
widely, often with a quivering or un- 
steady movement, and the thorax does 
not participate to the same extent as 
in normal respiration. The movements 
of the thorax may persist, altered in 
rhythm, to be sure, but nevertheless 
present, during yawning. I think that 
this is further evidence of the fact that 
yawning is related to the primitive 
mechanism.” 
Why Do Women Become Mothers? 
“The facts, shorn of sentiment,” 
says Mrs. Leta S. Hollingworth in the 
July Am. Journ. Sociology, ‘are: (1) The 
bearing and rearing of children is neces- 
sary for tribal or national existence and 
agerandizement. (2) The bearing and 
rearing of children is painful, dangerous 
to life, and involves long years of 
exacting labor and self-sacrifice. (3) 
There is no verifiable evidence to show 
that a maternal instinct exists in women 
of such all-consuming strength and fervor 
as to impel them voluntarily to seek 
the pain, danger and exacting labor 
involved in a high birth-rate.’’ The 
pressure of insidious forces set at work 
by certain “radiant centers of social 
control’’ has made women bear children 
in the past, she thinks, but she con- 
siders that her sisters are now on the 
eve of being emancipated, and that 
henceforth they will bear few children, 
unless they get “‘adequate compensa- 
tion, either in money or in fame.” 
