=GRUB IN THE HEAD.=--This condition is the presence of the larva (worm stage) of the sheep bot fly, located in the frontal sinuses (cavities) of the head. The trouble is confined to sheep and occasionally goats. The so-called “grub” of the horse is found in its stomach, while the “grub” of cattle is found along its back just underneath the skin. The adult fly, which lays the living “sheep grub,” is of a yellowish-gray color, slightly larger than a house fly. During the warmer part of the summer days the fly goes about depositing its young in the nose of the sheep. The young then work their way upward into cavities of the head between the eyes, but not into the brain cavity. Here they attach themselves to the lining, remaining when unmolested for some ten months, then lose their hold and are sneezed out to the ground. Burrowing into the ground they enter the pupa or dormant stage, when, after a month or six weeks, they emerge as adult flies to replenish their kind. When few grubs are in the head little trouble may be observed, but if more numerous may cause free discharge of dirty white or yellowish, thick fluid, loss of appetite, frequent coughing and sneezing, tossing of head and weakened gait, and the animal may become too weak to rise, and finally dies. With a special instrument (trephine) bore a hole into the cavity containing grubs and remove them with forceps. When they are present every year the sheep should be protected by keeping the nose smeared with tar during summer months. This can be done by causing sheep to lick salt from holes in a trough after placing tar about the holes. =HAIR BALLS.=--True hair balls are seldom found in other animals than cattle, resulting either from licking themselves or others; but different kinds of indigestible balls or concretions are frequently found in cattle and other animals, particularly the horse, in the stomach or intestines. Dust balls are occasionally formed when animals are fed upon mill cleanings. In sections where crimson clover is fed, and frequently in over-ripe condition in large quantities, balls are formed of parts of the indigestible heads. Again, calcareous or mineral matter may accumulate about an indigestible substance as a nucleus. These are not well-defined, in many instances, and the balls are often present without making it known. So long as they do not irritate the bowel too much, or do not occlude the opening from one portion of the bowel to another, they are likely to escape notice. In case they do obstruct the bowel they become serious obstacles, the greater number of these cases terminating in death. The symptoms then become those of colic from obstruction. In many cases no relief can be given, but attempts should be made to cause the obstruction to pass by giving mild purgatives and copious enemas.