DISEASES OF THE OX AND SHEEP. 659 



passage, should be tapped with a trocar and long canula, or by 

 means of a knife. If this be done, the cranium collapses, and 

 the calf will then be expelled, dead. The disorder may also 

 appear after birth, the cranial bones being thin and widespread. 

 Many stellate little bones called Wormian bones are placed 

 between them, so as to close up the large cavity so far as 

 possible. The brain, of course, suffers greatly in these cases. 

 Instances have been met with iu which the base of the skull is 

 the only part of it which is ossified. 



The same parasites as appear in the brain of sheep, viz. the 

 Coenuri cerehrales, may occasionally be present in the brain of 

 the ox. They are the immature forms of the Tcenia coenurus 

 which infests the dog. They affect various parts of the brain, 

 the cerebral hemispheres being most frequently]! attacked. The 

 Qgg of this tapeworm being swallowed, the embryo escapes, bores 

 its way through the tissues, enters a blood-vessel, and finally, 

 being carried in the course of the circulation to the brain, takes 

 up its abode there, and increases in size by absorbing the 

 substances around. When it is large, marked symptoms of 

 brain-disease are exhibited. The animal may lean the head to 

 one side, or may move round and round in the same direction 

 as that on which the parasite is situated, or the pressure of any 

 other kind is applied. The disorder is popularly known as 

 " turnsick," is most often seen in young animals, and is more 

 prevalent in some seasons than in others. Trephining may be 

 tried. 



Having thus discussed briefly certain diseases of the nervous 

 system intimately connected with the brain itself, we now proceed 

 to consider shortly those maladies which seem to be the result 

 of disturbance of the functions of the spinal cord. Yet, while 

 we are now writing down this statement, we cannot but feel 

 how impossible it is to clearly mark off disorders of the brain 

 from those of other parts of the nervous mechanism. Indeed, 

 so impressed are we with the difficulties of classifying nervous 

 diseases at all well that, before we pass on to the discussion of 

 the proper subjects for to-day, we take this opportunity of 

 pausing to see what Dr. Gowers teaches in regard to classifi- 

 cation of nervous disorders in mankind. 



" If we attempt," writes this well-known author, " to classify 



