Grape Culture. 45 



this is wrong, for leaves badly affected will curl inwards at the 

 margins. These leaves under the influence of the sun turn 

 pale, and ultimately yellow. Warts are not so prevalent in 

 houses which have been freely ventilated ; fresh air and less 

 atmospheric moisture will prevent this evil. An application of 

 sulphur to the pipes will turn every wart black, and show that 

 the vegetable matter is very sensitive to sulphurous fumes. 

 Prevention is thus better than cure, and, as I often say, some- 

 times our garden cures do much more harm than the disease. 



BLEEDING. 



Bleeding of vines is caused by a strong flow of sap which is 

 exuded from vines when recently pruned. Some growers 

 presume that vines will bleed to death. There is far more 

 stress laid on vine bleeding than there is any call for. There 

 is no doubt that the vine has an immense flow of sap provided 

 the border is moist, having been watered before growth com- 

 menced. The sap will flow until it finds an outlet, and here 

 the botanist will remember about the transpiration, respira- 

 tion, assimilation, and absorption of gases, known as the 

 function of leaves. I am here referring to the drops seen on 

 the apex of leaves when young vines are in the early stages of 

 growth caused by root pressure. Prevent bleeding by pruning 

 long before starting the vines. 



AERIAL ROOTS. 



Aerial or air roots are produced on the stems of the vine. 

 Canes will sometimes show these aerial roots at every joint. 

 Some think this is a sign of bad health in the vine. It is caused 

 by too close, moist, and warm an atmosphere. If a vine rod 

 was severed from its roots and placed in a close, warm house, 

 with abundance of atmospheric moisture aerial roots will be 

 produced in abundance. There is another cause still by which 

 aerial roots are produced, that is, by allowing the border to 

 become water-logged, or in any way unsuitable for the forma- 

 tion of healthy roots underground, and at a time when the vine 

 with its leaves and growing points, etc., are making a heavy 



