202 
-T. 0. MEYER, .TR. 
OSTEO POROSIS—“BIG-HEAD,” 
Paper read before the Ohio State Veterinary Medical Association. 
By Dr. J. 0. Meykr, Jr., D.V.S. 
In view of the unusual prevalence of this disease during the 
past nine months, I am induced to submit a paper setting forth 
the most prominent features of this creeping malady in order to 
institute a discussion of matter appertaining to it, thereby 
enabling us, if possible, to arrive at a definite conclusion as to the 
setiology, pathology, prophylaxis and treatment of this disorder. 
The term “Osteo Porosis” is described by Dunglison as 
follows: “Induration of a bone from the deposition of too much 
bony matter called osteo sclerosis. Also a bony degeneration, 
which consists in too great porosity with hardening.” 
“ RARIFACTION OF BONE.” 
This definition does not fully describe the conditions of bone 
in our patients affected with the disease we designate “Osteo Por¬ 
osis .” The porosity of the bone is manifested, but the induration 
does not exist; on the contrary, there is a lack of density of bone, 
an insufficient quantity of earthy material, consequently the bony 
structure becomes spongy. There is a distension of bony cells, a con¬ 
dition of hypertrophy, accompanied by serous infiltration. Th’s 
abnormal state of bones predisposes them to fractures. The 
superior and inferior maxillary are generally the first to undergo 
this change, hence the name “Big-head.” In the outset it is 
detected in the inferior maxillary bone; next the superior maxillary 
bone becomes involved, although other bones not so visible also 
become degenerated, as is often exemplified by the occasional 
fractures of bones of the extremities. It seldom occurs that a 
bone fractures completely, fragments of bone being broken off at 
the insertion of ligaments, tendons and muscles. 
The malady is unquestionably due to a blood poisoning and 
is in most cases attended by rheumatic lameness, located most 
frequently about the phalangeal region of one or more extremities, 
the shoulder, hip and hock joints, and even the lumbar vertebra, 
are also the seat of rheumatic pains and lameness. 
