424 C. CLIFFORD DOBELL. 



Sr 



a r c 1 11 a . 



After iiivestig-atiiig the structure of tlie ordinary Micro- 

 coccus forms, I naturally became curious to see what sort of 

 structures could be found in the Sarcinte. For some time 

 I endeavoured, to ascertain the exact structure of a Sarcina 

 Avhicli is veiy common in the English frog and toad, but I 

 was unable to reach any definite conclusions owing to the very 

 small size of the individual cells. Other Sarcina from other 

 animals proved equally difficult, but at last I discovered a 

 laro-e and suitable form in the large intestine of a Ceylon toad. 

 "This organism I will now describe. 



Sarcina3 from Bufo melanostictu s. 



These Sarciuie wei'e obtained from a single toad Avhicli 

 was captured near Colombo. All the preparations were made 

 by fixing in 1 per cent, osniic acid and staining with Griemsa's 

 stain. The following description therefore applies to organ- 

 isms treated in this manner. 



Sarcina is, of course, simply a colony of cocci, arranged 

 tvpically in groups of eight individuals in three dimensions of 

 space. The groups originate by the successive "cleavages" 

 — like a developing egg — of a single coccus cell. 



The individual cocci which compose the cell-groups of the 

 Sarcina under consideration are of very large size. They 

 measure on the average a little over 2 ^ in diameter — some 

 cells attaining a diameter of 2'5 jli. 



In the living organism, it can be seen that nearly every cell 

 contains one large refractile granule. This is probably reserve 

 material of some sort. Sometimes this granule may be absent 

 and occasionally two such structures are to be seen. No other 

 internal structures can be made out with certainty in the fresh 

 state. 



Upon staining the organisms, however, the structure of the 

 cell can be readily demonstrated (see figs. 24-29, PI. 16). The 

 cytoplasm appears a uuifoi-m blue,' and sometimes shows a 

 ' Or pink, if tlie l^liie is extracted with ideoliol after staining. 



