MAC 
himself well known by several useful and 
popular works on chemistry, of which sci- 
ence he was one of tlie most successful cul- 
tivators on the modern rational plan, before 
the new modelling which it has received of 
late years. His publications were “ Ele- 
niens de Chymie Pratique,”two vols. 12mo. 
17'5l-17.'r6. “ Plan d’lin Cours de Chymie 
experimentale et raisonn^e,” 12rao. 1757. 
This was drawn up in conjunction with M. 
Bailing, who lectured on chemistry in part- 
nership with him ; “ Dictionnaire de Chy- 
mie,” two vols. 8vo. 1766. These works 
have been translated into English and (Ger- 
man : the dictionary, particularly by Mr. 
Keir, with great additions and improve- 
ments. He wrote likewise “ FonnulEe 
Medicamentonim Magistralium,” 1763; and 
“ L’Art de la Teinture de Soie,” 1763; and 
he had a share in the Pharmacopeia Pa- 
risiensis,” of 1758. This meritorious writer 
died in 1784. Diet. Hist, de la Med. par 
Eloy. Nouv. Diet. Hist. 
MACROCEPHALUS, in natural his- 
tory, a genus of insects of the order Hemip- 
tera : snout inflected ; the sheath one- 
valved, three jointed, and furnished with 
three bristles ; antenna! projecting, very 
short, submoniliform, clavate ; head oblong, 
cylindrical above ; scutel as long as the ab- 
domen, depressed, membranaceous. There 
is only one species, riz. M. cimicoides, 
found in North America; the body is a 
ferruginous grey ; scutel pale ash with a 
yellow rigid spot ; under-wings purplish 
violet ; foi-e-shanks thickened. 
MACROCNEMUM, in botany, a genus 
of the Pentandria Monogynia class and or- 
der. Natural order of Contortre. Ru- 
biaceae, Jussieu. Essential character: co- 
rolla bell-shaped ; capsule two-celled, two- 
valved, with the valves gaping outwardly at 
the sides ; seeds imbricate. There are 
three species. 
MACROLOBIUM, in botany, a genus 
of the Triandria Monogynia class and order. 
Natural order of Lomentaceae. Legumi- 
nos®, Jussieu. Essential character ; calyx 
double, outer two-leaved, inner one-leaved ■ 
petals five, upper one very large, the rest 
small, equal ; germ pedicelled, legume. 
There are three species, all of them tall 
trees, from sixty to eighty feet in height ■ 
they are natives of the large forests of 
Guiana. 
M.ACROPUS, the kangiiroo, in natural 
history, a genus of raampialia of the order 
Fera!. Generic character : six front teeth 
in the upper jaw’, emarginated ; two in the 
MAC 
lower, and very long, sharp, large, and 
pointing forwards ; five grinders on each 
side of the upper and under jaw, distant 
from the other teeth ; fore-legs very short ; 
hind ones very long ; the female, with an 
abdominal pouch. This is one of the 
most curious ofall the animals discovered on 
the continent of New South Wales, where 
it was observed by some of the sailors of 
Captain Cook in the year 1770. When 
full grown it weighs about 150 pounds. Its 
head somew’hat resembles that of a deer, 
but is destitute of horns ; its countenance is 
gentle and complacent ; its colour is of a 
pale brown ; its length from the nose to the 
tail is betvyeen four and five feet, and the 
length of the tail is about three feet. Its 
general position, when resting, is that of 
standing on its hind feet, on their whole ex- 
tent to the knees, and its fore-feet are fre- 
quently employed, like those of the squirrel, 
as hands. They are often, however, laid on 
the ground, and the kanguroo is often seen 
in this posture, feeding. Vegetables, and , 
particularly grass, constitute its only nou- 
rishment. In its rapid motions, however, 
the fore-feet are wholly useless, and it pro- 
ceeds by leaping on its hind feet, which it 
will do to the distance of fourteen or six- 
teen feel, and with bounds so rapid in suc- 
cession, that it exceeds in swiftne,ss a com- 
mon dog. Kanguroos possess the faculty 
of separating at pleasure the two front teeth 
of their lower jaw; and the female is fur- 
nished with a pouch in the abdomen, of 
extraordinary depth, in w'hich are placed 
tw'o teats. But one young one is produced 
at a time, which, when first observed in the 
pouch, after its birth, is scarcely more than 
an inch in length, but grows to a consi- 
derable size in this natural receptacle before 
it quits it, and frequently recurs to it for 
warmth and security after its first dislodg- 
ment from it. This animal is in this strik- 
ing circumstance allied to the oimssum ge- 
nus, under which Gmelin ranks it, but it 
differs from the opossum materially in re- 
.speet to the structure of the teeth. In its 
general appearance it strongly resembles 
the jerboa. It was the only quadruped 
which Australasia supplied to the Ensriish 
colonists for food. It has been not only 
imported into England, but has repeatedly 
bred in this country, and may be considered 
as now naturalized ; and though not appa- 
rently convertible to any important service, 
exhibits a very interesting variety to the 
observer of nature. Many of these ani- 
mals are kept in the royal premises at Kew, 
