the fruit was attacked hy the disease, while the cork layers were swelling, 

 the specked tissue had already lost its elasticity. 



The dying of single tissue groups of this kind as the result of an in- 

 sufficient storage of reserve substances will take place so much the more 

 easily as the deposition of starch is made more difficult by the one-sided in- 

 creased nitrogen fertilization. In fact, practical fruit growers have also 

 observed that this specking is especially abundant, if the trees have been 

 excessively fertilized with sprouted malt, hornshavings, etc. 



Wortmann^ substantiates our theory in regard to the non-parasitic 

 character of the specks and of their occurrence with a scarcity of water. 

 He ascribes the appearance of the dead cork cell groups to an excess of acid 

 which is brought about by the concentration of the cell sap of the fruit as 

 a result of unreplaced water loss. The absolute acid content decreases with 

 the ripening of the fruit, but the relative acid content becomes increased 

 with, scarcity of water in the cells. Wortmann concludes from his investi- 

 gations of the epidermis that the larger fruits evaporate more than the 

 smaller ones and the specked varieties (reddish Reinette, Goldgunderling, 

 King of Pippins, Landsberger, green Stettiner, Danziger) evaporate more 

 than do the varieties not inclined to specks. He found a greater thickening 

 of the outer walls of the epidermis in the non-specked varieties, the peeled 

 specimens of which evaporated more than did peeled specked apples. If 

 the fruit of non-specked varieties was pricked with a needle and laid in acid 

 or alkaline solutions (potassium, tartarate, limewater) specks were pro- 

 duced which could not be distinguished from natural ones. 



The phenomenon of the so-called "fly specks" should not be confused 

 with this. Very fine little black points united into groups are found on the 

 apple peel, which appear to the naked eye like a cloudy bloom and under the 

 microscope look like accumulations of fly specks. Fungi, especially 

 Leptoihyrium pomi Mntg. and Fr. and Phyllachora Pomigena (Schw.) 

 Sacc. are given as the causes. Often actual insect secretions are found in 

 which fungi grow. Since the skin under the "fly-specks" does not seem to 

 have been injured in any way, rubbing with a damp cloth is enough to make 

 the fruit again fit for sale. Another phenomenon, often called specking, is 

 the "rusting of the peel." This term comes from the change in color of 

 the outer skin. During the process of sivelling, the skin gets stellate or den- 

 tritically-branched tears, which are closed by the formation of cork. 



Stoniness of Pears and Lithiasis. 



When pears are grown on poor soils, in dry years the flesh is solid, but 

 grates between the teeth when eaten, in wet years the flesh is tender and does 

 not grate between the teeth. This grating is due to the extraordinarily large 

 amount of stone granules formed in the years of drought. Practical workers 

 often maintain the theory that the formation of stone cells in pears is the 

 direct result of great drought. 



1 Wortmann, Jul., Ueber die sog. Stippen der Aepfel. Landwirtsch. Jahrbiichcr 

 1892, Parts 3 and 4. 



