28 



The Rot in Sheep. 



The gentleman thus alluded to is Mr. Blacklock, from whose 

 writings we have before quoted. He says, — 



" The lungs are always the principal, and I may also, from my own expe- 

 rience, add, the primary seat of the affection. When examined in the early 

 stage of rot, they have a hard lumpy feel, especially at the upper part or lobe ; 

 :>nd at this time a great number of irregular yellowish-white, patchy-looking 

 bodies will be seen shining through the membrane, pleura, which surrounds 

 the organ. These tubercles, as the hard white bodies are called, vary in size 

 from that of a mustard-seed to that of a pea. They are sprinkled through all 

 parts of the lung, and will, in every dissection, be found in a variety of stages, 

 from the firm condition in which they were deposited, to the softened state 

 which denotes their speedy expectoration. Each tubercle, however small, 

 usually holds a particle of calcareous matter in its centre." 



The confidence with which Mr. Blacklock speaks of the 

 matter will be further shown by one other short extract from 

 his writings : — 



" Fluke-worms and hydatids are almost constant attendants on rot, and 

 seemingly most important ones, especially the former, which have, I may say, 

 kept a great bulk of the learned and unlearned for many years in a perpetual 

 bustle, and have so hoodwinked writers on this subject as to prevent them 

 seeing the truly important points of the disease." 



These opinions, although thus authoritatively put forth, re- 

 specting rot being a tuberculous disease of the lungs have in 

 reality no true foundation. Indeed, as has been already pointed 

 out, sheep are not subject to depositions in their respiratory organs 

 of this aplastic material, which proves so destructive to mankind. 



The little hard lump about the size of a " mustard-seed," 

 holding calcareous matter, mistaken for a true tubercle, is the 

 product of the Strongylus filaria. Examined in the early stages 

 of its formation, and when it presents little more than an ecchy- 

 mosed condition, or occasionally approaching to a pus-like 

 deposit, a male parent-worm will be seen coiled upon itself in 

 the isolated miliary body. Having served the chief purpose of 

 its life, the entozoon is about to die and become entombed in 

 calcareous matter, his own structure contributing to this end by 

 being involved in the process of calcification. Similar changes 

 we believe to take place with the female parent-worms, but 

 these, from their increased size and number, produce depositions 

 exceeding in size those of the male entozoa. 



In the still larger and softer deposits, which give here and 

 there to the lung a flesh-like appearance, myriads of ova and 

 young strongyles of both sexes will be found, which, by their 

 local irritation, produce the changed lung-structure in which 

 they dwell. Such are the revelations of the microscope, and 

 very satisfactorily do they elucidate one form of parasitic 

 disease to which sheep are remarkably prone. 



Among the advocates of the opinion that rot depends on 



