PRINCIPLES OF VETERINARY SURGERY 647 



case is not one of fcetal rachitis. Independently of the fact 

 that the latter is very rare, it is not manifested by analogous 

 lesions, but by osseous incurvations and a special constitu- 

 tion of tjhe bones, which are first fibrous then osseous. 

 Neither is it a case of contracture. -- 



Dareste has shown that the affection is a lesion of a me- 

 chanical order caused by amniotic compression. As it is 

 impossible to connect other osseous lesions with those of 

 bulldog calves, further research as to its nature must be 

 made. 



PATHOGENESIS.— The cause of achondroplasia is 

 still unknown, although some light has been thrown on the 

 subject recently. It is well known that the long bones, car- 

 tilaginous in the foetus, are transformed into osseous tissue 

 by two processes, — periosteal ossification., which enlarges 

 the transverse diameter, and enchondlral ossification, that 

 lengthens them. It is readily seen that the first process is 

 not altered, as the bones have the normal diameters. Ac- 

 cordingly the cause of the alteration must be connected 

 with enchondral ossification. Achondroplasia has been ob- 

 served chiefly in Normandy calves. Fourreau met with a 

 total of seventeen cases, the mothers of which had all been 

 served with same bull. Parturition is usually easy, only oc- 

 casionally proving rather annoying to the obstetrician. 



SNIFFLING DISEASE OF THE HOG. 



DEFINITION. — Sniffling disease is a microbian affec- 

 tion manifested by fibrous transformation of the bones of the 

 head, especially the maxillaries. It is a chronic affection 

 showing no tendency to recover,. and invariably termiriating 



fatally. 



HISTORY. — The first account of the disease must be 

 credited to Hurtreld and Arboval, who reported an out- 

 break in the Duchy of Nassau in 1832. i'rodal, the first 



