_S. bronchialis_, found by Castellani in 1907 in cases of bronchitis in Ceylon. The parasites are delicate, but show morphological variation. This organism is important and has since been found in the West Indies, India, Philippine Islands and various parts of Africa, such as the Anglo-Egyptian Sudan, Uganda and West Africa. It has recently been the subject of research by Chalmers and O’Farrell, Taylor, and Fantham. _S. phagedenis_ was found by Noguchi in a ten days old ulcerated swelling of the labium. The organism shows much variation in size, being 4 µ to 30 µ in length. _S. refringens_ (Schaudinn, 1905) occurs in association with _Treponema pallidum_ in syphilitic lesions, but is non-pathogenic. It is 20 µ to 35 µ long and 0·5 µ to 0·75 µ broad, being larger than _T. pallidum_ and more easily stained. Various spirochætes have also been notified in vomits, chiefly in Australia; others from the human intestinal tract, _e.g._, _S. eurygyrata_; _S. stenogyrata_ (Werner); _S. hachaizæ_ (Kowalski), in cholera motions; _S. buccalis_ (Cohn, 1875) and _S. dentium_ occurring in the human mouth and in carious teeth (_S. dentium_, Koch, 1877, being the smaller); _S. acuminata_ and _S. obtusa_ found by Castellani in open sores in cases of yaws. Animal spirochætes of economic importance include:-- _S. anserina_, highly pathogenic to geese. _S. gallinarum_ (= _S. marchouxi_) in fowls. (See p. 119.) _S. theileri_ in cattle and _S. ovina_ in sheep also occur in Africa; their pathogenicity is not clear. _S. laverani_ (= _S. muris_), occurring in the blood of and pathogenic to mice, is probably the smallest spirochæte from the blood, being only 3 µ to 6 µ long. Numerous spirochætes have been recorded from the guts of various mammals, birds, fishes, amphibia and insects. CULTIVATION OF SPIROCHÆTES.--Cultures of spirochætes have been made with little success or with great difficulty until comparatively recently, when Noguchi (1912) devised a means whereby he has cultivated most of the pathogenic spirochætes as well as some Treponemata. Noguchi has now cultivated _S. duttoni_, _S. recurrentis_, _S. rossii_, _S. novyi_ and _S. gallinarum_ from the blood; _S. phagedenis_[157] from human phagedænic lesions; _S. refringens_[158] and spirochætes from the teeth. [157] _Journ. Exptl. Med._, xvi, p. 261. [158] _Journ. Exptl. Med._, xv, p. 466. His method is as follows:--