Practical bacteriology, microbiology and serum therapy (medical and veterinary) : a text book for laboratory use / by A. Besson ; translated and adapted from the fifth French edition by H.J. Hutchens.

  • Besson, Albert, 1868-
Date:
1913
Catalogue details

Licence: In copyright

Credit: Practical bacteriology, microbiology and serum therapy (medical and veterinary) : a text book for laboratory use / by A. Besson ; translated and adapted from the fifth French edition by H.J. Hutchens. Source: Wellcome Collection.

    838/928 (page 806)
    the flea; on the contrary, it is an exceptional and aberrant method (Minchin and Thomson). Appearance in the blood.—In fresh blood, T. lewisi is flattened and fusiform and often twisted on itself. It is the most motile of all the Trypanosomes and vigorously displaces the red cells : it may sometimes be seen moving across the preparation like a dart with the flagellum in front. Its length including the flagellum is 24—25fj., its breadth T5/j. (Laveran and Mesnil). Its protoplasm is finely granular; the [tropho-] nucleus is not visible but the centrosome [kineto-nucleus] appears as a retractile spot to- wards the posterior end. In preparations fixed and stained by Laveran’s method (p. 772) the protoplasm is stained pale blue with fine granules; the [tropho-] nucleus, oval in shape and situated in the anterior one-third of the body, is stained lilac. The undu- lating membrane is unstained—with the exception of its free thickened border which is stained lilac—and is continued anteriorly into the flagellum, while posteriorly it takes origin from the centrosome which is stained deep violet. In the blood of rats which have been infected for a long time only fully developed fusiform tr}Tpanosomes are seen, all of the same length. To study the multiplication forms it is necessary to prepare stained films from the blood of a rat which has been inocu- lated intra-peritoneally 4-8 days previously. The peritoneal exudate, which contains numerous multiplication forms during the first 2 or 3 days, is not a very suitable material for the study of the cytology of the parasites. Before dividing, the Trypanosome increases in size, the centrosome approaches the nucleus and the flagellum thickens at the end which is in relation to the centrosome. Soon the nucleus and centrosome as well as the base of the flagellum divide. The newly formed flagellum separates from the original one and though at first much shorter than the latter, it rapidly elongates while the protoplasm is dividing. The young Trypanosome finally separates but may again subdivide before detaching itself. Other multiplication forms have the appearance of spherical or oval bodies in which the nuclei and centrosome having approached each other divide (into from 2 to 16 parts), and the flagella at the same time split into two without the protoplasm dividing: then the protoplasm shows a series of notches around its periphery (rosette appearance) and finally divides into as many parts as there are nuclei. The small parasites resulting from the segmentation of the rosette may again in their turn divide. Appearance in cultures.— Novy and MacNeal were able to grow the organism on their blood-agar medium (p. 799) : growth takes place best at the tem- perature of the laboratory and is poorer at 34°-37° C. These observers have FIG. 388 —Try- panosoma lewisi stained by Laver- an’s method. (After Laveran and Mesnil.) x about 2000 dia- meters. b Fig. 389.—Trypanosoma letoisi. Leishman’s stain. x 1000.