1909] 77c Lift History of Trypanosoma Dimorphon. 129 



to prevenl evaporation. In such a preparation the trypanosom.es 

 will live but a few hours, and even when kept on a warm stage 

 seem to be under unfavorable conditions. We have never even 

 observed a trypanosome complete the whole process of division, 

 and therefore Eresh examination, which is usually of such great 

 importance, lias in this case been very unproductive of results. 



Until recently the only method of staining blood parasites 

 entailed the process of drying, and results obtained after employ- 

 ing such an unsatisfactory method are evidently untrustworthy. 

 In consequence of the various object ions to it to which attention 

 was first called 1>\ Slavin-Moore and Breinl (1907), the use of 

 dried films has been abandoned ami their method employed. 



A very thin layer of albumen is smeared over a clean slide. 

 On this a drop of blood, or piece of an organ, is smeared out in 

 the usual way and the slide immediately dropped face down- 

 wards into a jar of Plemming's strong solution. After fixation 

 for about five minutes the slide is taken out, washed in water, 

 and then passed through successive alcohols up to absolute. It 

 is then taken back into Sll per cent, alcohol containing iodine and 

 potassium iodide in such quantity as to produce a dark brown 

 solution. After about ten minutes the slide is taken out. passed 

 down to 30 p*' cent, alcohol, and then stained by either of the 

 following methods : 



m The film is stained in a solution of aniline safranin 

 Babes) for about one hour; then washed in water and stained 

 in a 1 per cent, aqueous solution of polychrome methylene blue 

 for another hour. The blue is then washed off and the film 

 differentiated with Unna's orange tannin as long as dark clouds 

 are seen to come out. After washing in water the slide is passed 

 up through the alcohols into absolute, and thence into aniline 

 oil. (The passage through the alcohols must be as rapid as pos- 

 sible owing to the extraction of the stain that takes place.) 

 Thin the film is cleared in xylol and mounted in Canada balsam. 



(b) The film is mordanted for one hour in a 3.5 per cent, 

 aqueous solution of iron alum and then stained for an equal 

 length of time in a 0.5 per cent, aqueous solution of haemo- 

 toxylin, artificially ripened by the addition of a few drops of 



