POULTRY DISEASES AND THEIR TREATMENT. 207 



Hypertrophy. — The morbid enlargement or overgrowth of an organ or 



part. 

 Immunity. — Securit}^ against any particular disease. 

 Infection. — The transmission of disease from one animal to another 



usually through some intermediate agent. 

 Infiltration. — The accumulation in a tissue of substances not normally 



found in it. 

 Inoculation. — The insertion of a virus into a wound or abrasion in the 



skin in order to communicate a disease. 

 Isthmus. — See p. 158. 



Keratitis. — Inflamation of the cornea of the eye. 

 Larva. — The first stage in development after leaving the egg. Used 



in connection with insects, worms, etc. 

 Larynx. — A muscular and cartilaginous structure situated at the base 



of the tongue and connecting with the windpipe 



(trachea). It is the organ of voice. 

 Lesion. — Any hurt, woimd or local degeneration. 

 Leucocytes. — White blood corpuscles. 

 Lyinphafic._ Pertaining to or containing lymph which is a transparent 



slightly yellow liquid which fills the lymphatic ves- 

 sels. It corresponds in some respects to the serum 



or liquid portion of the blood. 

 Mammal. — Any vertebrate animal which suckles its young. 

 Melanosis. — Pertaining to an abnormal deposit of pigment. 

 Mesentery. — The fold of peritoneum attached to the intestines. 

 Metamorphosis. — In insects the change from larval to adult form as from 



caterpillar to butterfly. 

 Micro-organism. — Any minute (microscopic) animal or plant. Often 



used in referring to bacteria or germs. 

 Mite. — A small arthropod somewhat related to spiders. (Cf. fig. 31). 

 Mucosa. — The mucous membrane. 



Mucous membrane. — The lining of the internal cavities of the body. 

 Mucus. — The viscid secretion of certain (mucous) glands. 

 Mycelium. — The thread-like portion of a fungus. (Cf. fig. 38). 

 Nacreous. — Resembling mother-of-pearl. 

 Necrotic. — Pertaining to dead or decaying tissue. 

 Nucleus (PI. nuclei). — A spherical body within a cell. The nucleus is 



essential to the life of the cell. 

 Oesophagus. — That portion of the alimentary canal between the mouth 



(pharynx) and the crop. 

 Oral. — Pertaining to the mouth. 



Ovary. — The female sexual organ in which the eggs develop. 

 Oviduct. — The tube through which the egg passes from the ovary to the 



cloaca. 

 Ovum, (plural ova).— The- egg, particularlv while on tlie ovary. 



(Cf. fig. 40). 

 Panophthalmia. — Inflammation of all the structures or tissue of the eye. 

 Papilla. — A small nipple shaped elevation. 

 Pathology. — That branch of m.edicine which treats especially of the tissue 



changes caused by disease. 



