UMB 



URE 



ging matter. Ulcers sometimes be- 

 come torpid and dilllcult to heal, in 

 which case stimulants are used. The 

 application of caustic is necessary 

 when there is fungous growth ; the 

 nitrate of silver or red precipitate is 

 best. Calomel is extremely service- 

 able to heal healthy ulcers : tar is also 

 used for this purpose. 



ULTIMATE ANALYSIS. The 

 determination of the elements of an 

 organic body. See Organic Analysis. 



UMBEL. In botany, a form of in- 

 florescence in which all the pedicels 

 proceed from a single point. If there 

 is no subdivision, the umbel is called 

 simple ; hut if the pedicels produce 

 otlier umbels, as in parsley, the um- 

 bel is compound. 



UMBELLIFER.E, UMBELLIF- 

 EROUS PLANTS. They are a race 

 of great frequency in all cool or 

 temperate climates, and even occur 

 in hot ones, tliough much more rare- 

 ly. They are known in general by 

 their flowers being disposed in an 

 umbel. They have an herbaceous 

 stem ; leaves usually much divided, 

 often inflated wiien they join the 

 stem ; and they have universally a 

 dry fruit, which divides into two seed- 

 like pieces. Some of them are poi- 

 sonous, as hemlock, fool's parsley, 

 and water dropwort ; others are es- 

 culents, as celery, carrots, and pars- 

 nips ; many yield aromatic fruits, as 

 caraway, coriander, and anise ; a lew 

 secrete a fojtid gum resin, of which 

 asafcEtida, ammoniacum, and galba- 

 num are examples. The species are 

 extremely numerous, and difficult to 

 recognise with accuracy ; and, un- 

 fortunately, no general rule has yet 

 been discovered for distinguishing 

 the poisonous from the harmless 

 kinds ; but those whicii grow in damp 

 or wet places are to be suspected, 

 whereas those that are aromatic and 

 found in dry soils are often innocuous. 



UMBILICAL CORD. In animals, 

 the cord of blood-vessels which pass- 

 es between the placenta and fcetus ; 

 the navel string. In botany, the 

 thread which attaches the seed to the 

 carpel or placenta. 



UMBILICUS. The navel. 

 818 



UNCIFORM BONE. One of the 

 bones of tiie wrist. 



UNCONFOR.MABLE STRATA. 

 Strata whicli do not incline or dip in 

 the same direction as those below or 

 above tlicm. 



UNDERWOOD. Coppice, small 

 trees, or shoots from old stools. 



UNGUIS. The claw or small ex- 

 tremity of a petal, where it is insert- 

 ed into the stem. 



UNGULATES. Those quadrupeds 

 furnished with a hoof 



UNILOCULAR. Seed vessels 

 which contain but one cavity. 



UPAS. A Javanese tree, from 

 which the upas poison is secreted ; 

 the Anliaris toxicana. 



UPONG. Ilex vomiCoria and cassi- 

 na. The black drink, medicine, or 

 tea plant of North Carolina, used by 

 the Indians. 



UREA. A peculiar crystallizable 

 substance held in solution in the urine. 

 When dried in vacuo it consists, ac- 

 cording to Dr. Prout, of, 



Atoms. Experiment. 



Nitrogen 2 45 65 



Carbon 2 20 07 



Uvdrogen 1 6-65 



Oiygeu 4 26- C3 



T lOOUO 



Urea is readily soluble in water, 

 tasteless, inodorous ; and when mix- 

 ed with the other contents of the 

 urine, very prone to putrefaction, the 

 principal result of which is carbonate 

 of ammonia. 



UREDO. "As the diseases of 

 corn occasioned by fungi belonging 

 to the genus Urcdo are of great im- 

 portance, we shall describe them 

 particularly. In the article Burned 

 Ear, a diseased state of wheat is de- 

 scribed, in which the Urcdo segetuin 

 appears. 



I " Urcdo caries, De Candolle (U. 



I fatida, Bauer), is found on wheat ; 

 the sporidia are included within the 

 ovary of the fruit, and are exactly 

 spherical, rather large, globose, and 

 black. When this plant appears on 

 wheat it is said to have the bunt, 

 smut-balls, or pepper-brand. The 



: sporidia may be detected in the young 

 seed in the very earliest states of 



I the flower-bud, and when perfectly 



