472 DISEASE IN WILD MAMMALS AND BIRDS 
in the causation of neoplasms. Attention is arrested how- 
ever by the paucity of tumors in derivatives of the ecto- 
derm since in man new growi:hs are common in the breast, 
at the rectal and labial mucocutaneous j mictions and on 
the sMn. The immunity of the ectodermic tissues to 
secondary growi:hs is very distinct ; this holds true in man. 
Special Tumoes. 
The diagnosis of fibroma offers the same difficulty in 
the zoological material as it does in man and even more 
care must be exercised for solid tumors in certain locali- 
ties. The bird often presents hard nodular masses on the 
palmar and lateral aspects of the feet, sometimes sur- 
mounted by callosities, to wliich the term fibroma or fibro- 
matous corns might be applied. Section of some of these 
will reveal areas of granulation tissue about points of 
inflammation so that we have considered them as infec- 
tious or the result of incorrect perches and excluded them 
from the tumors. True fibromata have been encountered 
thrice but in combination with muscle tissue as a fibro- 
myoma thrice in addition. The '' fibroids " seen in the 
elephants and armadillo have already been described. 
The nodular gro^vth sometimes accompanying degen- 
erative disease of the osseous system followed by 
attempts at repair as discussed under osteitis deformans, 
leontiasis ossium and actinomycosis, are often produc- 
tive of masses to which it is easy to apply the term 
osteoma. If one demand that an osteoma shall be a dis- 
tinct neoplastic, localized bony growth of unnatural or 
greatly exaggerated structure, then the tumor is quite 
rare. We have seen one growing from the vertebrae and 
cla^'icle of a gerbille and a fibro-osteoma on one jaw of an 
Isabelline gazelle. The chondromata have been limited 
to one case, a unilateral mass growing from the nasal 
cartilage of a caracal. 
Lipomata are localized collections of fat consisting of 
cells with greater fat capacity than normally, sometimes 
