476 BACTERIOLOGICAL ANALYSES 



(B) Anaerobes (Vegetative Forms and Spores). 



16. Pour similar sets of plates in glucose formate 

 gelatine and agar and incubate in Bulloch's anaerobic 

 apparatus. 



(C) Aerobes and Anaerobes (Spores Only). 



17. Pipette 5 c.c. soil water into a sterile tube. 



1 8. Place in the differential steriliser at 80 C. for 

 ten minutes. 



19. Pour two sets of four gelatine plates containing 

 o.i, 0.2, 0.5, and i c.c. respectively of the soil water; 

 label and incubate at 20 C., one set aerobically, the 

 other anaerobically in Bulloch's apparatus. 



20. "Count" the plates (delay the enumeration as 

 long as possible) and estimate the number of spores 

 of aerobes and anaerobes respectively present per 

 gramme of the soil. 



21. Calculate the ratio existing between spores and 

 spores + vegetative forms under each of the two groups, 

 aerobic and anaerobic micro-organisms. 



Qualitative Examination. The qualitative examina- 

 tion of soil is usually directed to the detection of one 

 or more of the following : 



Members of the Coli-typhoid group. 



Streptococci. 



Bacillus anthracis. 



Bacillus tetani. 



Bacillus cedematis maligni. 



The nitrous organisms. 



The nitric organisms. 



1. Transfer the remainder of the soil water (88 

 c.c.) to a sterile Erlenmeyer flask by means of a sterile 

 syphon. 



2. Fix up the filtering apparatus as for the qualita- 

 tive examination of water, and filter the soil water. 



3. Suspend the bacterial residue in 5 c.c. sterile 



V 



