LABOKATORY AND GREENHOUSE STUDIES. 115 



minutes, respectively, otlicr plates were poured. For inoculation 

 one 3-mm. loop from the flask was used. 



A similar set of plates was made from 250 c. c. mercuric clilorid 

 (1 to 5,000) and from 250 c. c. sterile; water. In all three cases inocu- 

 lations were of the same amount and from the same culture, and tlie 

 plates were poured at the same intervals of time. The plates were 

 incubated at 33° C. 



After 24 hours the plates poured from sterile water had numerous 

 colonies (about 1,500 in each plate). The plates from HgClg 1 to 

 1,000 had a total of two colonies; the plates from HgClj 1 to 5,000, a 

 total of three colonies. 



After 9 days no more colonies had developed in the plates from 

 the HgCl2 solutions. 



Another experiment with similar strengths of HgClg was made 

 with plates poured at end of 20, 30, and 40 seconds. 



No colonies appeared even after six days at 33° C. The check 

 plates from sterile water gave 450 to 500 colonies in 24 hours. 



MONOCALCIUM PHOSPHATE. 



Two solutions, A and B, were made up, each containing 1 per cent 

 peptone, 1 per cent dextrose, 0.5 per cent sodium chlorid and neutral 

 red, and into A was put 1 per cent monocalcium phosphate and into 

 B, 0.1 per cent. The amount of calcium phosphate in normal 

 coconut tissues is 0.05 per cent. 

 After 1 day: A tubes were clear. 



B tubes were well clouded, but had produced no change in color. 

 After 16 days: A tubes were perfectly clear. 



B tubes all moderately clouded with moderate amount of precipi- 

 tate. No change in color. 



PEPTONE SOLUTION CONTAINING ROSOLIC ACID. 



Two solutions, A and B, were made up, each containing 1 per cent 

 Witte's peptone and sulTicient rosohc acid to make a bright red, and 

 into A was put 1 per cent dextrose. 



After 1 day: A tubes were yellow; good growth. 

 B tubes remain red; good growth. 

 After 4 days: A tubes were orange yellow; well clouded. 

 B tubes unchanged in color; well clouded. 

 After 11 days: A tubes, same as before. 

 B tubes, same as before. 



This experiment was repeated, and the colors in the tubes were 

 compared with the color chart of the Repertoire de Couleurs: 

 A check tubes were pink. 



A culture, tested after 17 days, resembled honey yeUow, tint No. 3. 

 B check, a trifle darker than the culture tubes. 

 B culture, tested after 17 days, resembled cardinal red, tint No. 1. 

 228 



