in Lambs and Young Sheep. 
507 
1. That condition recognised as "rickets," "weak back," 
or " paralysis " of lambs, peculiar to animals the progeny of 
ewes which have been fed during the middle and latter periods 
of gestation upon materials, generally turnips, grown upon 
certain soils under particular conditions of cultivation. 
2. A condition in which the bones of the skeleton, chiefly 
of the limbs and of young sheep, gradually become decalcified, 
rendering them unfit to serve the purposes of passive organs 
of locomotion, and liable to be fractured from trivial causes. 
That these two conditions, apparently so dissimilar in their 
attractive features, are in their essential nature the same, 
I hope to be able to prove as we advance in the consideration 
of the subject, and, in particular, as we examine the character 
of the chanse which has occurred in the bone-elements in each. 
In the one, that recognised by the terms of " rickets " or 
*' weak loins," which has hitherto been regarded as a primary 
disease of the nerve centre, the spinal cord, there appears 
evidence to satisfy that this latter structure is only affected 
in a secondary manner ; the primary inducing factor being 
change in the bone-elements forming the canal in which the 
cord is lodged. In the other, bone-softening and fragility are the 
result of nutritive changes occurring: in the bones themselves. 
In the one case the bone changes are mainly, if not entirely, 
confined to the central or axial portion of the skeleton ; while 
in the other, the limbs or appendicular parts are the situations 
of the change. Both these manifestations of disturbed bone 
nutrition possess the common feature of liability to appear 
on soils of the same general character, such soils evidently 
influencing the character of the food supplies which are grown 
thereon. 
1. — "Rickets," " Weak Loixs," or "Paraplegia." 
General Characters and Distribution. — This condition of 
impairment, or loss of power, of movement, specially of the 
hind extremities, although occurring occasionally amongst 
sheep of one year old, is unquestionably in an especial sense 
a disease of lambs, many of which, in decided outbreaks of the 
disease, are seriously affected from their birth. The affection, 
when fairly developed, has no tendency to recovery, rather 
may we expect aggravation of symptoms or a fatal issue. The 
localities where this affection is encountered, although they 
may be widely separated, are on examination found to possess 
many features and characters in common. The soil is of 
a light or moory character, containing much vegetable matter 
resting on what is known as " moor band " or " moor pan," 
2 L 2 
