Cultivation of the Trypanosome found in the Blood of the Gold-fish

Abstract

1. The trypanosome of the gold-fish has been successfully cultivated on the medium of McNeal and Novy.2. Preparatory to division in culture, the original trypanosome as found in the blood of the fish assumes a somewhat tadpole-like appearance, the endoplasm and its contained structures being collected together in the swollen posterior end. The kineto-nucleus now lies close to, and alongside of, the tropho-uncleus, and the latter has become swollen and loose in structure with its chromatin broken up into chromidia. The anterior third or more of the trypano-some undergoes little or no change in form and does not take part in division. It is thus easily seen how the product of the preliminary division comes to have a Crithidia-like appearance.3. The product of this preliminary division—Crithidia-like by the relative position of kineto-and tropho-nuclei—is capable of freely multiplying.According to Brumpt it is in the Crithidia-like form that free multiplication of the eel trypanosome first takes place in the stomach of Hemiclepsis. It may well be that in this case also the Crithidia-like form is arrived at by steps such as are here figured and described.4. Crithidia-like forms are found at all stages of the culture and along with them at various stages other forms where the body is elongated and the kineto-nucleus still close to the tropho-nucleus, and yet other forms where the kineto-nucleus until true trypanosome-like forms are reached.5. These trypanosome-like forms (resembling mammalian trypanosomes rather than those of the fish from which they are derived) are most numerous in the later stages of the culture.