914 
to a reed-pipe,’ and suggests the resemblance 
between the vocal band action and the lip action 
in blowing a horn. Whether the lips in blow- 
ing a horn vibrate laterally as reeds or by com- 
pression as cushions, I am unable to say ; they 
may quite possibly vibrate in a manner differ- 
ent from that assumed by Helmholtz.* 
EH. W. SCRIPTURE. 
YALE UNIVERSITY, 
NEW HAVEN, CONN. 
PHYSIOLOGY IN THE SCHOOLS. 
To THE EDITOR OF SCIENCE: Judging from 
the letter of 8S. W. Williston in your issue of 
May 24th, people must acquire their mental 
growth much more rapidly in Kansas than they 
do in the East. If I were confronted in an ex- 
amination for the degree of doctor of philosophy 
with the question ‘Why does the human body 
cease to grow about the twenty-fifth year?’ I 
should think there were strong grounds for 
suspecting the examiner of endeavoring to show 
what I did not know, even at the price of ask- 
ing questions whose answers I could not know. 
Yet we are told that this question has been 
asked of candidates for the State teacher’s 
certificate. The theory of accelerated mental 
development is furthermore strongly supported 
by the apparent fact that children are ex- 
pected, by the time they finish with the gram- 
mar school, to know about pleurisy, the res- 
piratory center, residual air, appendicitis, 
meatus auditorius and the motores ocult. 
If mental development is anywhere as rapid 
as these facts would suggest, there- can, of 
course, be no criticism with regard to the con- 
* Misunderstanding the point under discussion and 
supposing that Professor Le Conte was speaking of lat- 
eral vibrations of the lips and vocal cords, Professor 
Webster (Clark Univ.), replies to him in SCIENCE 
for May 24, N.S., Vol. XIII., p. 827, that 
the action of the lips and the vocal cords Be 
had already been explained by Helmholtz 
and that his description of 1862 ‘has never + Bayt 
needed any improvement or correction.’ 
Professor Webster asserts that he regards the 
simple model of a membranous reed pipe 
with a sheet of rubber in lateral vibration as ‘a very 
convincing demonstration of the mode of action of 
the larynx.’ He also classifies elastic cushions as 
‘reeds.’ 
SCIENCE. 
£¥3 
~Ba; W; 
[N. S. Vou. XIII. No. 336. 
sideration of these questions in physiology at 
the time indicated. 
If, however, children generally show about 
the same rate of mental development as I have 
observed in the East, the writer would like to 
suggest that if less time were consumed in the 
contemplation of useless details of anatomy, re- 
lieved by worse than useless rambles into 
pathology, and more in the plain, common 
sense, practical study of the conditions of 
healthy living, teachers would no longer learn 
in examination papers that ‘the body should be 
bathed frequently, should be bathed at least 
once a year.’ There is, in fact, a horrible sus- 
picion in the mind of the writer that some- 
thing else than the text-book is at fault. 
THEODORE HouGH. 
MASSACHUSETTS INSTITUTE OF TECHNOLOGY, 
May 25, 1901. 
SHORTER ARTICLES. 
THE GENERAL EQUATIONS OF ROTATION OF A 
RIGID BODY. 
AFTER writing my brief note on the top, * it 
occurred to me that the same method might be 
used to derive the Eulerian equations of rota- 
tion briefly and at once, in a way almost pic- 
* This Journal, May 31, 1901. 
