﻿86 MIYAJIMA. 



the same as that used by Rogers. 10 The blood containing intracellular 

 parasites, is drawn from the jugular vein and then quickly defibrinated 

 under strict precautions so as to avoid bacterial contamination; it is 

 then directly mixed with ordinary nutrient bouillon in proportions vary- 

 ing from one-fifth to one-tenth, and placed aseptically in sterile test- 

 tubes which thereafter are maintained at a temperature of 20° to 30° C. 

 The development of the parasites in a successful culture takes place in 

 the following manner : On the first day no motile form is seen ; on the 

 second, there can be observed a certain number of peculiar cells which 

 occupy the upper layer of sedimented corpuscles and which macro- 

 scopically appear as a series of whitish dots. Very few motile forms 

 resembling typical trypanosomata are visible in these cells on the third 

 day after incubation, but thereafter the trypanosomata multiply vigor- 

 ously and reach the maximum number between the tenth and fourteenth 

 day. (PI. Ill, fig. 12.) 



In a culture kept at room temperature, the trypanosomata remain 

 motile until forty-five days later, at this time most of them have under- 

 gone degeneration and globular cells with irregular granulations result. 

 In a culture preserved at a lower temperature, ranging from 10° to 20° 

 C, the organism on the contrary remains alive until three months 

 after the 'maximum number has been reached. It is noteworthy that sub- 

 cultures are also readily obtained by inoculating from the original strain 

 into a new blood bouillon, as in the case of Trypanosoma lewisi. 



The most important factor in securing the multiplication of the para- 

 sites essentially consists in great precautions in avoiding the slightest 

 contamination with bacteria, as is the case with other cultures of protozoa. 



We have already made miscroscopical examinations of the blood in 

 over 200 cattle and among them not one has proved to be infected with 

 trypanosomata; moreover, all varieties of bovine trypanosomiasis are 

 entirely unknown in our country, at least up to the present time no 

 one has demonstrated a case of such infection. 



As is well known, there are many protozoan parasites which infect a 

 living host without the latter manifesting any pathological symptoms; 

 it is also a fact that microscopic examination is not as delicate a means 

 for the detection of a small number of parasites as is the cultural method, 

 which is essentially used in the study of bacteria. From a consideration 

 of these conditions it seems more natural at once to consider the tryp- 

 anosoma-like flagellates found in our cultures to be true trypanosomata, 

 which, owing to their extremely small number in the original blood, 

 would fail of detection by means of the microscopical examination alone. 



However, the relation between piroplasma and trypanosoma, although 

 supported by the views of Schaudinn and other observers, is still a question 



"Lancet (1905) 1, 168-1. 



