The numerous small blisters or vesicles thus derived coalesce, forming a large sac full of "blister-fluid."
Similar spraying is recom- (From a specimen in the British Museum.) mended for pear-leaf blister Pear Scab (Fusicladium pyrinum).
His disorder was an oedematous affection of the wind-pipe, contracted by exposure during a long ride in a snowstorm, and aggravated by neglect and by such contemporary remedies as bleeding, gargles of "molasses, vinegar and butter" and "vinegar and sage tea," which "almost suffocated him," and a blister of cantharides.
Plum-leaf blister is caused by Polystigma rubrum, a pyrenomycetous fungus which forms thick fleshy reddish patches on the leaves.
Thick are carburized and so converted into high carbon " blister steel," by heating them in contact with charcoal in a closed chamber to about 1000° C. (1832° F.) for from 8 to ii days.
For long all the best high-carbon steel was made by remelting this blister steel in crucibles (§ 106), but in the last few years the electric processes have begun to make this steel (§ 108).
The great extension of surface thus produced had the drawback of exaggerating any small defect in the union of the two metals, increasing it to a blister of an inch or more in diameter.
The blister if unbroken was heated, pricked, and then rubbed level with a burnisher; if, as sometimes happened, the silver had flaked away it was replaced by coatings of pure leaf silver rubbed in with a burnisher.
As a result, certain varieties, such as blister steel, are called " steel " solely because they have the hardening power, and others, such as low-carbon steel, solely because they are free from slag.
In Great Britain the charge usually consists of blister steel, and is therefore high in carbon, so that the crucible process has very little to do except to melt the charge.