ISO Report of the Botanist of the 



Tlirco tubes of this medium carefully neutralized with sodium 

 hydroxide, aud three tubes unneutralized were inoculated with the 

 spongy tissue and kept 24 days in air at a temperature of about 

 80° Fahr. Six other tubes of the same medium, three neutralized 

 and three unneutralized, were inoculated and kept for the same 

 length of time at a temperature of about 80° Fahr. in an atmos- 

 phere devoid of oxygen. No growth appeared in any of the 

 twelve tubes. 



From the result of this study we conclude that the form of 

 apple fruit-spot described above is not caused by fungi or bacteria, 

 but what the real cause may be we are not prepared to state. 



Wortmann^ observed that starch is present, often in considera- 

 ble quantity, in the brown, spongy tissue, while the surrounding 

 healthy tissue is almost, if not wholly, destitute of starch. We 

 find that the spongy spots lying just beneath the epidermis gen- 

 erally contain considerable starch, but the deeper-lying spots 

 (which, as has been stated, are formed after the fruit is gathered) 

 rarely contain more than traces. This difference in starch con- 

 tent is brought out very strikingly when a section of apple show- 

 ing both kinds of spots is smeared with a solution of iodine and 

 potassium iodide. The sub-epidermal spots become black, showing 

 the presence of starch, while the interior spots are not altered in 

 color. 



When an apple is bruised without breaking the epidermis the 

 tissue becomes brown and sjDongy and resembles somewhat the 

 brown,' spongy spots under discussion. We have found this 

 bruised tissue loaded with starch, while the surrounding unin- 

 jured tissue contained no starch. Green apples contain starch 

 which is changed into sugar as the fruit ripens. It, therefore, 

 seems probable that the bruises which responded to the test for 

 starch were made before the fruit was ripe. Upon the death of 

 the cells their activities ceased and the transformation of starch 

 into sugar was arrested. This theory accounts for the absence of 

 starch from late formed spots. 



23Loc. cit., p. 663. 



