438 BACTERIA OFTEN EMPLOYED IN LABORATORY PRACTICE 



irregular in outlines and flow together forming a thick, moist, lemon- 

 colored growth. 



Sarcina aurantiaca forms an orange-yellow pigment; Sarcina alba 

 a white, and Sarcina rubra a red pigment. Sarcina mobilis is remark- 

 able for the fact that it is motile and, as claimed, possesses a flagellum. 

 Sarcina ventriculi is found in the gastric contents of man and animals. 

 The individual cocci are very large (up to 2.5 micra in diameter) and 

 they are found in groups of eight. Whether Sarcina ventriculi is a 

 definite species or not, or simply represents varieties of sarcinae taken 

 up with food or water, is a question not yet settled. 



QUESTIONS. 



1. What is the relation of members of the proteus group of bacilli to proteid 

 material? 



2. Why have these bacilli received the name proteus? 



3. Describe the variability of their shape. 



4. Describe the morphology and the cultural properties of Bacillus proteus 

 vulgaris. 



5. What is meant by the swarming islands of a proteus gelatin culture? 



6. Has the Bacillus proteus any pathogenic properties? 



7. What is the Bacillus anthracoides? 



8. -What is a megatherium? 



9. Describe the Bacillus megatherium and state why it has received this 

 peculiar name. 



10. Describe the Bacillus prodigiosus. Why so named? 



11. Are there other chromogenic bacilli which produce a red pigment? 



12. Describe the Bacillus violaceus. Is it ever pathogenic? 



13. Describe the Bacillus cyanogenus. 



14. Describe the Micrococcus tetragenus. What does tetragenus mean? 



15. Is this micrococcus pathogenic for any animal? 



16. What unusual feature does the Micrococcus agilis possess? 



17. What is a sarcina in general? Describe the Sarcina lutea. 



18. Describe the Sarcina aurantiaca. 



19. Where is Sarcina ventriculi found? 



