448 Brooks: The Fruit Spot of apples 



Neutral litmus milk-tubes were inoculated and were watched 

 for any indication of acidity. The lavender color disappeared only 

 to give place to the brown of the whey. 



Some culture material which had originally been solution A 

 but which had had the fungus growing on it for more than five 

 months, produced but an extremely scant growth after sterilization 

 and reinoculation. Tests were made to determine whether the 

 reduction in growth was due to the production of some harmful sub- 

 stance or to lack of food material. 25 c.c. of this used solution 

 were placed in each of fourteen 100 c.c. flasks. To two of these 

 was added as much of each of the original food materials as had been 

 added to an equal quantity of water in the beginning. In another 

 two the peptone content was increased as described above but the 

 solution left otherwise unchanged. The other food constituents 

 were added to other flasks in a similar manner, and two flasks were 

 left unchanged as controls. The flasks were all inoculated with 

 the usual fungus. The ones to which all the original constituents 

 had been added gave a luxuriant growth of the fungus. The 

 flasks to which sugar had been added came next in amount of 

 development and those in which the apple content had been in- 

 creased came third. The addition of peptone increased the growt 

 but the flasks to which beef extract and sodium chloride had been 

 added gave no better development of the fungus than wasobtaine 

 in the controls. These results would suggest that the fungus 

 failed to make the usual development in old culture media because 

 of lack of food material rather than from any harmful compo ,,n 

 produced, and also that the acidity of the solution must have #1 

 decreased by the growth of the fungus. Beef extract and so in* 

 chloride were evidently not used by the fungus in the quantt y 

 which they were added to solution A. _ , . 



Efforts were made to determine whether the browning 

 accompanied the fungus in the apple tissue and also in various 

 Culture media was due to an enzyme or other product of the u b 

 Strips of sterile uncooked apple tissue were dropped into ^ 

 solution A previously described and also into a similar bu ^ 

 solution. After three weeks the tissue was unaffected in ^ 

 these. This old solution was also added to tubes of milk _ 

 change in color was apparent. Some of the old culture so 



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