URE 



URI 



not so certainly prevented as smut, 

 although there is reason to bclievi; 

 that the sporiiles of the V. ruhigoare 

 taken less up by the roots, in the 

 same manner as those producing 

 smut. As a dressing, the use of the 

 lime-water or sulphate of copper 

 should never be neglected ; although 

 it may not always prevent rust, yet 

 there are instances recorded in which 

 undressed wheat has had rust, when 

 dressed wheat from the same sample 

 has not had it. 



" Connected with the question of 

 blight in corn is one that has produ- 

 ced much discussion, and that is, how 

 far the barberry {Berbcris vulgaris) is 

 the cause of it. There is a very 

 general impression among farmers 

 that the barberry-bush produces rust 

 in corn, and there are numerous well- 

 authenticated instances of blight oc- 

 curring in the vicinity of barberry- 

 bushes and hedges. Botanists, not 

 seeing how this could occur, have 

 generally treated the fact as a coin- 

 cidence, and acquitted the barberry 

 altogether of the crime of producing 

 blight ; but the evidence of blight oc- 

 curring as the consequence of the 

 presence of the barberry is constant- 

 ly increasing. One of the best ex- 

 planations of this curious circum- 

 stance is, that the barberry itself is 

 subject to the attacks of a fungus, 

 the ^cidium berberidis, similar to that 

 which produces the disease in wheat. 

 The specific characters of the two, 

 however, are very different, and it 

 is only by having recourse to the 

 supposition that many of the record- 

 ed species of JEcidium are merely 

 varieties changed in character by 

 change of position, that such an ex- 

 planation of the fact can be admitted. 



" Besides the species of uredo men- 

 tioned, corn and all other plants are 

 subject to the attacks of a large num- 



ber of these fungi. On whatever 



plant they are found they are indica- 

 tive of disease, and the produce of 

 the plant will not be so great as 

 when in a state of health. Sir 11. 

 Davy found that 1000 parts of good 

 wheat yield, on an average, 955 parts 

 of nutritious matter, while specimens 

 from mildewed wheat yielded only 

 from 650 to 210 parts in the same 

 quantity." See, also, Mildew. 



URETERS. The tubes which con- 

 vey urine from the kidneys to the 

 bladder. 



URETHRA. The passage from 

 the bladder outward, lor the discharge 

 of urine. 



URIC ACID, LITHIC ACID, .^n 

 acid occurring in large quantity, com- 

 bined with ammonia, in the urine of 

 birds and reptiles, and to a small ex- 

 tent only in the urine of carnivorous 

 (juadrupeds. In the pure state it is a 

 very insoluble white powder ; it dis- 

 solves in nitric acid, and when evap- 

 orated to dryness and mixed with a 

 little ammonia, gives the rich red col- 

 our of miirexide. The composition 

 of uric acid is Cio H4 rS4 0,^ : it is con- 

 verted by putrefaction into bicarbo- 

 nate of ammonia. Peruvian guano 

 contains eight to twenty per cent, of 

 this acid, hut the African is usually 

 without it. 



URINE. The fluid excrement of 

 quadrupeds : in birds and reptiles it 

 is solid. The urine contains the 

 greatest portion of the nitrogenized 

 matters of the excrements, and is 

 therefore the most important portion 

 of manure. The composition of hu- 

 man urine is given in the article 

 Night Soil, the management of that 

 of the cow under the article Flanders 

 Husbandry . 



" The efficacy of urine as a manure 

 depends upon the quantity of solid 

 matter which it holds in solution, 



Nut in milk. When in milk, about half of this. 



820 



