344 LEON AUGUSTUS HAUSMAN. 



for supplying water to take the place of that carried off by 

 evaporation (Fig. 3). 



The method of removing individual Amoeba from stender 

 dishes was as follows, and can be used with success for the isola- 

 tion of any of the larger protozoan forms : A drop of water con- 

 taining the Amozbtz was placed upon an ordinary slide, and, 

 uncovered, searched with the 16 mm. objective and 8 X eye- 

 piece. When Amoeba were located they were removed by means 

 of what is termed an isolation pipette (Fig. 2). A long rubber 

 tube attached at one end to a glass tube drawn out to a very 

 fine tip, and at the other to a small compression bulb, enables 

 one to select and withdraw very minute objects with considerable 

 precision. Both the stender dishes and growing slides were kept 

 at a temperature of 80 degrees Fahr. in a large aquarium jar 

 heated by a carbon filament lamp placed in the bottom, the 

 current being controlled by a rheostat. By means of this simple 

 device unvarying temperatures could be maintained for any 

 desired length of time. The advantage of such a culture oven is 

 that light is admitted freely on all sides (Fig. i). 



FORMATION OF APSEUDOPODIOSPORES. 



One of the stender dishes which had been inoculated with 

 adult Amoeba protens proved very productive, the individuals 

 increasing rapidly, apparently by means of binary fission, since 

 many were observed in process of division. The bodies of the 

 largest individuals became filled with minute bodies, which upon 

 staining seemed to be nuclei. The individuals bearing these were 

 extremely sluggish. The pseudopodia were short ; exhibited very 

 little movement, changed their shape but slowly, and upon the 

 functional posterior of the body absent altogether (Fig. 5). 



After an interval of four days had elapsed a reexamination of 

 some of the sediment from the same stender dish was made and 

 it was found that the numbers of the large proteus had appre- 

 ciably decreased and that their places were taken by a multitude 

 of very small amoeboid forms, of an average diameter of 4 or 5 

 microns. The majority of these exhibited feeble movements of 

 an amoeboid kind. Some were globular, some possessed an 

 irregular body outline, though definite pseudopodia were lacking 



