RADIOSA TYPES 43 



forms were grown on live slides with augmented 

 auxetics a gradual change in appearance took 

 place. Employing two live slides, No. 1 con- 

 taining equal volumes of 0'2-per-cent. creatine 

 and choline, and No. 2 equal volumes of 0-5-per- 

 cent, solutions of these substances, two distinct 

 types of amoeba were obtained, which are called 

 for convenience Radiosa types 1 and 2. Type 1 

 (fig. 20) was obtained with the weaker auxetic, 

 and shows a central body composed of granular 

 protoplasm, with long, blunt pseudopodia radiating 

 irregularly from the centre. Progression is by a 

 kind of rolling motion, and changes in the form 

 of the pseudopodia are very sluggish. This type 

 was very persistent, and was cultivated for weeks. 

 Commencing with only the normal forms, the 

 majority of amoeba* had assumed this form in 

 about ten days. Type 2 (fig. 21) was of rarer 

 occurrence, and chiefly differed from type 1 in 

 the pseudopodia being very much longer, and 

 thinned out to very fine filaments at their distal 

 ends, and alterations in the shape of the pseudo- 

 podia were much more rapid than in type 1. By 

 the jelly method, it was found that these forms 

 are more difficult to stain than the ordinary forms, 

 thus showing that their coefficient of diffusion has 

 been raised during their morphological changes. 

 Although the solutions in which they were ob- 

 tained were slightly alkaline, the effect must be 

 attributed to the auxetics and kinetics present, as 

 they could not be cultivated in pure alkaline 

 solutions of various strengths, and have been grown 

 for some generations on a neutral 2-per-cent. agar 

 jelly containing 0'2-per-cent. creatine only, and 



