(_b_) Maintain sanitary drinking fountains with fresh water to avoid spreading infection by way of water. Take special care to prevent dampness from spillage or leakage around the drinking fountain, as this makes an ideal place for bacteria to accumulate. (_c_) Feces from birds with diarrhea should be removed from the loft as soon as noticed. (_d_) Frequent disinfection of the loft with a strong disinfectant like 4 percent saponified cresol will help keep down contamination. _c._ TRICHOMONIASIS. This is a very common disease of pigeons commonly seen in the mouth, esophagus, or crop in the form of cheesy yellow or white lesions. For this reason it is often called “canker” by pigeon fanciers. The cause is a motile one-celled organism. Only the common type of this organism will be considered here. This disease has many carriers. It shows up only where sanitary conditions are bad or other diseases are present. (1) _Symptoms._ The course of the disease varies according to resistance of the affected bird, treatment, and care. Young birds in the nest become infected through “milk” of infected parents. Infection doubtless spreads by contact while “billing” and fighting. Germs cause affected tissues to die. This results in the formation of a sore or opening down into the tissue with a varying-sized yellow, cheesy exudate or scab forming over it. Sometimes such scabs become very large and nearly fill the mouth, throat, or crop. (2) _Treatment._ Various drugs and chemicals have been used to treat trichomoniasis. However, this condition has proved quite unresponsive to usual medication. In fact, drugs do not have much, if any, direct effect on the healing of tissue. All that medicine can do is to cut down the number of parasites present and permit nature to repair the damage done to the tissue. Suggested procedures for treatment follow: (_a_) Remove all yellow pus patches with cotton swabs. Then paint area with a mixture of iodized oil and sulfanilamide powder. The iodized oil is prepared by using 1 gram iodine, 1.5 grams potassium iodide, and 2 ounces light petrolatum. The iodine requires some time and frequent shaking to dissolve. Make a small cotton swab on an applicator stick, dip it into the oil, roll it in the sulfanilamide powder, and then apply to cleaned trichomoniasis (canker) lesion. Daily treatment, rest, and an abundance of good feed are necessary. (_b_) Clean off exudate by local applications of tincture of iodine, or a mixture of one part iodine to three parts glycerine; at the same time lesions will respond to such treatment. Silver nitrate may be used either in stick form or in solution. (3) _Prevention._ Sanitation is the best preventive. (_a_) Correct predisposing causes such as wet floors, nests, and perches. (_b_) Try to isolate infected birds, provided the number is not too large.