198 DISEASES OF DOMESTICATED BIRDS 
violent cough will expel them. The operation in question can be 
performed by one person, for a syringe with two rings on the barrel 
can be guided easily with one hand. The sick bird is held between 
the knees with the breast in front. The neck is bent up and back 
with the left hand and the trachea lies between the thumb and index 
finger. Next, the syringe lying conveniently, is grasped with the 
right hand. The needle is placed near the trachea, after which with 
necessary care it is inserted into the trachea slanting downwards and 
the injection made quickly. The introduction of a dull canula into 
the glottis through the beak is even more suitable than the foregoing 
method. After the injection the bird suffers a light attack of 
choking but soon recovers. 
A very safe but a somewhat less effective remedy is to cause the 
affected birds to breathe air containing finely powdered chalk and 
camphor. Theobald recommends a mixture of two parts by weight 
of powdered chalk and one part of powdered camphor. This is 
dusted into a closed box in which the chickens are confined. 
Prevention. Contaminated water and soil are to be regarded as 
the chief sources of infection. Infectious larve have been kept alive 
for a year in moist soil. Chicks raised on board floors and thus iso- 
lated from the soil with separation from older birds until a month 
or six weeks old, will escape infection provided the water and food 
supply are not infected. Rotation in the use of land to which chicks 
are allowed access is a valuable practice in avoiding the use of con- 
taminated soil from year to year. Above all, chickens should not be 
kept on soil that has been occupied by turkeys within a year or so. 
Disinfection of drinking vessels and of soil, so far as possible, de- 
serves consideration. Salicylate of soda, 3 drams to the quart of 
drinking water is said to kill the embryo worms. Contaminated soil 
may be disinfected by drenching with a one per cent solution of sul- 
phuric acid. Wet areas should so far as possible be dried by drain- 
ing. 
The isolation of the sick and thorough disposal of the dead are 
obvious precautions. 
THE AIR SAC MITE 
Cytoleichus (Cytodites) nudus has a wide distribution in the 
United States and Europe affecting a large number of gallinaceous 
fowls and also pigeons. The mites are barely large enough to be de- 
tected by the unaided eye. They have been observed in the trachea, 
