60 THE ROYAL SOCIETY OF CANADA 



find organisms in all the stages already mentioned, the majority will 

 appear as irregular spheres in clusters varying in size, shape and num- 

 ber of individuals to the cluster. In Aj and A^, these clusters are 

 very irregular in shape, sometimes occurring as short chains. See 

 PI. II, Fig. 7; and PI. Ill, Fig. 3. In A, and A^ they are more of the 

 conventional tetrad and sarcina forms with the faces of contact flat- 

 tened. See PI. Ill, Figs. 6 and 9. 



Involution fonns occur in old cultures of each variety. These 

 aie often many times larger than the normal organism and are very 

 irregular in shape, being usually much swollen in one or more parts 

 and constricted in others. They are usually granular and give the 

 glycogen reaction. Chains of ten to thirty cells are common in Ashby's 

 liquid cultures after two weeks cultivation. 



Very striking involution forms occur in cultures incubated at 

 37°C., most particvilarly so with cultures of A^. With this variety, 

 many of the organisms elongate into long threads, 30-60 ft x 4-8 fx, 

 varying in thickness and in the appearance of their internal contents, 

 which may be granular with spherical granules varying in size or more 

 or less homogeneous. See PI. II, Figs. 8 and 9. They also vary in 

 response to stains. When the temperature is reduced to 25°C., the 

 involution forms once more gradually approach the normal shape 

 and size, the long thread forms becoming constricted at intervals, 

 thus forming chains. 



Motility. 



Motility is common in young cultures 24-48 hours old on Ashby's 

 agar and in liquid cultures. A few motile cells may also be found in 

 older cultures. The motility of the Ag and A^ varieties is, generally 

 speaking, more rapid and vigorous than that of the Ai and A, varieties. 

 Flagella stains of 24 hour old cultures on Ashby's agar, made according 

 to Moore's modification of Loeffler's flagella stain, show each variety 

 to possess two kinds of flagella. The one kind is long and delicate and 

 in each variety appears to be produced in considerable numbers, 5-20, 

 preceding disintegration of a cell. There seems to be a close relation- 

 ship between these flagella and the motile gonidia which are dispersed 

 on disentegration of a cell. See PI. V, Figs. 2, 7, 8, 9, 10, 11, 12. The 

 other kind is comparatively short, except in the case of Aj, relatively 

 strong and stains deeper than the first mentioned kind and appears to 

 be more permanent in character. See PI. II, Fig. 3, and PL V, Figs. 

 3, 4, 5, 6. With Aj, this second kind is long, being comparatively 

 thick near the body of the organism and tapering to a delicate thread 

 at the other extremity. See PI. V, Fig. 1. The flagella, whilst they 



