or by heating pyruvic acid with an excess of acetic anhydride and sodium
acetate to 160-180 deg. C. (B. Homolka, _Ber._, 1885, 18, p. 987). It
crystallizes in needles (from hot water) which melt at 72 deg. C. and
boil at 180-181 deg. C. It is moderately soluble in cold water. It
combines directly with bromine, and, with fuming hydrobromic acid at 100
deg. C., it gives chiefly [alpha]-brombutyric acid. With hydriodic acid
it gives only [beta]-iodobutyric acid. Potash fusion converts it into
acetic acid; nitric acid oxidizes it to acetic and oxalic acids; chromic
acid mixture to acetaldehyde and acetic acid, and potassium permanganate
to [alpha][beta]-dioxybutyric acid.
Isocrotonic acid (Quartenylic acid) is obtained from
[beta]-chlorisocrotonic acid, formed when acetoacetic ester is treated
with phosphorus pentachloride and the product poured into water, by the
action of sodium amalgam (A. Geuther). It is an oil, possessing a smell
like that of butyric acid. It boils at 171.9 deg. C., with partial
conversion into crotonic acid; the transformation is complete when the
acid is heated to 170-180 deg. C. in a sealed tube. Potassium
permanganate oxidizes it to [beta][gamma]-dioxybutyric acid.
Methacrylic acid was first obtained in the form of its ethyl ester by E.
Frankland and B. F. Duppa (_Annalen_, 1865, 136, p. 12) by acting with
phosphorus pentachloride on oxyisobutyric ester (CH3)2.C(OH).COOC2H5. It
is, however, more readily obtained by boiling citra- or
meso-brompyrotartaric acids with alkalis. It crystallizes in prisms,
which are soluble in water, melt at 16 deg. C., and boil at 160.5 deg.
C. When fused with an alkali, it forms propionic acid; with biomine it
yields [alpha][beta]-dibromisobutyric acid. Sodium amalgam reduces it to
isobutyric acid. A polymeric form of methacrylic acid has been described
by F. Engelhorn (_Ann._, 1880, 200, p. 70).
CROTON OIL (_Crotonis Oleum_), an oil prepared from the seeds of _Croton
Tiglium_, a tree belonging to the natural order Euphorbiaceae, and
native or cultivated in India and the Malay Islands. The tree is from 15
to 20 ft. in height, and has few and spreading branches, alternate,
oval-oblong leaves, acuminate at the point, and covered when young with
stellate hairs, and terminal racemes of small, downy, greenish-yellow,
monoecious flowers. The male blossoms have five petals and fifteen
stamens; the females have no petals but a large oblong ovary bearing
three bifid styles. The fruit or capsule is obtusely three-cornered, and
about the size of a hazel-nut; it contains three cells each enclosing a
seed. The seeds resemble those of the castor-oil plant; they are about
half an inch long, and two-fifths of an inch broad, and have a
cinnamon-brown, brittle integument; between the two halves of the kernel
lie the large cotyledons and radicle. The ocular distinction between the
two kinds of seeds may be of great practical importance. The most
obvious distinction is that the castor-oil seeds have a polished and
mottled surface. The kernels contain from 50 to 60% of oil, which is
obtained by pressing them, when bruised to a pulp, between hot plates.
Croton oil is a transparent and viscid liquid of a brownish or
pale-yellow tinge, and acrid, peculiar and persistent taste, a
disagreeable odour and acid reaction. It is soluble in volatile oils,
carbon disulphide, and ether, and to some extent in alcohol. It contains
acetic, butyric and valeric acids, with glycerides of acids of the same
series, and a volatile body, C5H8O2, tiglic acid, metameric with angelic
acid, and identical with methylcrotonic acid, CH3.CH:C(CH3)(CO2H). The
odour is due to various volatile acids, which are present to the extent
of about 1%. A substance called crotonal appears to be responsible for
its external, but not its internal, action. The latter is probably due
to crotolinic acid, C9H14O2, which has active purgative properties. The
maximum dose of croton oil is two minims, one-fourth of that quantity
being usually ample.
Applied to the skin, croton oil acts as a powerful irritant, inducing so
much inflammation that definite pustules are formed. The destruction of
the true skin gives rise to ugly scars which constitute, together with
the pain caused by this application, abundant reason why croton oil
should never be employed externally. Despite the pharmacopoeial liniment
and the practice of a few, it may be said that this employment of croton
oil is now entirely without justification or excuse.
Taken internally, even in the minute doses already detailed, croton oil
very soon causes much colic and the occurrence of a fluid diarrhoea
which usually recurs several times. It is characteristic of this
purgative that it is a hydragogue even in minimal dose, the fluid
secretions of the bowel being most markedly increased. The drug appears
to act only upon the small intestine. In somewhat larger doses it
produces severe gastro-enteritis. The flow of bile is somewhat
increased. Such effects may all be produced, even up to the discharge of
blood, by the absorption of croton oil from the skin.
The minuteness of the dose, the certainty of the action, and the large
amount of fluid drained away constitute this the best drug for
administration to an unconscious patient (especially in cases of
apoplexy, when it is desirable to remove fluid from the body), or to
insane patients who refuse to take any drug. One drop of the oil, placed
on the back of the tongue, must inevitably be swallowed by reflex
action. A dose should never be repeated. The characters of this drug
obviously contra-indicate its use in all cases of organic disease or
obstruction of the bowel, in pregnancy, or in cases of constipation in
children or the aged.
CROUP, a name formerly given to diseases characterized by distress in
breathing accompanied by a metallic cough and some hoarseness of
speech. It is now known that these symptoms are often associated with
diphtheria (q.v.), spasmodic laryngitis (q.v.), and a third disease,
spasmodic croup, to which the term is now alone applied. This occurs
most frequently in children above two years of age; the child goes to
bed quite well, and a few hours later suddenly awakes with great
difficulty in inspiration, the chest wall becomes markedly retracted,
and there is a metallic cough. The child becomes cyanosed, and, to the
inexperienced nurse, seems in an almost moribund condition. In the
course of four or five minutes, normal respiration starts again, and the
attack is over for the time being; but it may recur several times a day.
The seizure may be accompanied by convulsions, and death has occurred
from dyspnoea. The best treatment is to plunge the child into a warm
bath, and sponge the back and chest with cold water. Subsequently this
can be done two or three times a day. Should the cyanosis become very
severe, respiration can be restarted by making the child sick, either
with a dose of ipecacuanha wine, or by forcing one's finger down the
throat. Generally the bowels should be attended to; and the throat
carefully examined for enlarged tonsils or adenoids, which if present
should be treated.
CROUSAZ, JEAN PIERRE DE (1663-1750), Swiss writer, was born at Lausanne.
He was a many-sided man, whose numerous works on many subjects had a
great vogue in their day, but are now forgotten. He has been described
as an _initiateur plutot qu'un createur_, chiefly because he introduced
at Lausanne the philosophy of Descartes in opposition to the reigning
Aristotelianism, and also as a Calvinist pendant (for he was a pastor)
of the French _abbes_ of the 18th century. He studied at Geneva, Leyden
and Paris, before becoming (1700) professor of philosophy and
mathematics at the academy of Lausanne, of which he was four times
rector before 1724, when the theological disputes connected with the
_Consensus_[1] led him to accept a chair of philosophy and mathematics
at Groningen. In 1726 he was appointed governor to the young prince
Frederick of Hesse-Cassel, and in 1735 returned to Lausanne with a good
pension. In 1737 he was reinstated in his old chair, which he retained
to his death. Gibbon, describing his first stay at Lausanne (1752-1755),
writes in his _Autobiography_, "the logic of de Crousaz had prepared me
to engage with his master Locke and his antagonist Bayle."
The most important of his works are: _Nouvel Essai de logique_ (1712),
_Geometrie des lignes et des surfaces rectilignes et circulaires_
(1712), _Traite du beau_ (1714), _Examen du traite de la liberte de
penser d'Antoine Collins_ (1718), _De l'education des enfants_ (1722,
dedicated to the then Princess of Wales), _Examen du pyrrhonisme
ancien et moderne_ (1733, an attack chiefly on Bayle), _Examen de
l'essai de M. Pope sur l'homme_ (1737, an attack on the Leibnitzian
theory of that poem), _Logique_ (6 vols., 1741), _De l'esprit humain_
(1741), and _Reflexions sur l'ouvrage intitule: La Belle Wolfienne_
(1743). (W. A. B. C.)