LABORATORY BACTERIOLOGY. 



EXEECISE XLV. 



TIIK EFFECT OF INOCULATION AS SliOWN BY THE GROWTH OF 

 LEGUMES IN" TUBES. 



1. Tlioroughly wash the seeds of the legumes to be used 

 (alfalfa, red clover, sweet clover, etc.) and immerse in a 

 mercuric chloride solution (1: 500) for 5 minutes. 



2. Place between the folds of filter paper wrung out of the 

 same solution, and put in a warm place until dry. 



3. Then drop one or two seeds of each legume into a large 

 lube containing a loose mass of filter paper covered with 10- 

 20 ce. of "Badicicola" solution. 



4. Arrange thus : 



1 & 2— Alfalfa. 



3 & 4 — Alfalfa, Inoculated with alfalfa organisms. 

 5 & 6 — Alfalfa, inoculated with sweet clover organisms. 

 7 & 8 — Sweet Clover, inoculated with alfalfa organisms. 

 9 & 10 — Sweet Clover, inoculated with sweet clover organisms. 

 11 & 12 — Red Clover, inoculated with alfalfa organisms. 



5. The seeds used are inoculated according to the plan 

 given in (4) from pure cultures of the organisms obtained 

 in the previous exercise. 



6. After growth has taken place examine carefully for 

 nodule formation and note the location, numbers and size of 

 the nodules formed. 



7. Describe the general effects of cross-inoculation, com- 

 paring the cross inoculated with the straight inoculated 

 plants. 



