_Latent or occult glanders_ is often met with, the indolent, specific lesions being confined to some internal organs, like the larynx, lungs or womb, or to the testicles, the nasal diagnostic symptoms being absent. A chronic cough, with a slight purulent discharge from the nose, a chronic leucorrhœa, a swollen testicle, or simply a persistent low condition or weakness without apparent cause, may be the only indications, and special means of diagnosis are demanded. _Special Means of Diagnosis._ In occult cases, the disease may be identified by inoculation, or by the mallein test. _Inoculation_ is best performed on a very susceptible animal. If the suspected discharge from the nose, vagina, open sore or preferably from a freshly incised nodule is inoculated subcutem in the flank of a male Guinea pig, or better in the peritoneum, there develops a local ulcerous sore and on the second or third day a violent orchitis in which pure cultures of the bacillus can be obtained. The caseous and purulent centres are found not only in the testicle but along the line of the spermatic cord, affecting the tunica vaginalis and connective tissue. Death usually follows in four to fifteen days. The cat and dog can also be utilized, inoculation being made on the forehead. Old wornout, but otherwise healthy asses, and even horses make very available subjects, inoculation in the nose speedily developing acute glanders. In the absence of a good subject the suspected animal is sometimes availed of, scarifications being made in the nose and the morbid product rubbed in freely. The rapid development of ulcerous wounds is characteristic. If, however, the case is chronic, and if a fair measure of immunity has been acquired this test may prove misleading. _Test by Mallein._ Mallein is the sterilized and concentrated toxic product obtained from a pure culture of bacillus mallei in a peptonized glycerine bouillon. When injected hypodermically in a small physiological dose this has no effect on a sound horse, but in one affected with glanders it develops in several hours an extended swelling in the seat of inoculation, hot, tense and painful, which continues to enlarge for 24 to 36 hours and does not subside for 4 or 5 days. From the margin of the swelling, swollen lymphatics may often be traced running toward the adjacent lymphatic glands. There is also decided dulness, prostration, inappetence, staring coat and tremors. The body temperature rises 1.5° to 2.5° and upward from the eighth hour after inoculation attaining its maximum from the tenth to the eighteenth hour and subsiding slowly to the forty-eighth to the sixtieth.