12 '' Reversion" and Resistance to '' BUj Bud" 



(4) The leaf is sharp pointed, abnormally narrow, with a more than 

 usually serrate margin. 



While in badly attacked bushes all these points may be observed at 

 once it is much more common to find only some of them. 



The disease is nearly always gradual in its appearance and frequently 

 parts of a bush will show signs while the rest is quite healthy. Until the 

 eye becomes trained it is easy to pass over bushes which are only begin- 

 ning to revert. 



While from the practical point of view the failure of the fruit is 

 undoubtedly the most important point it is not in the author's opinion 

 the most crucial for the elucidation of the disease. If the theoretical 

 explanations afterwards to be considered are correct it is clear that the 

 extensive outgrowth of lateral wood precedes the running off in point of 

 time and may serve to explain the latter. In discussing the disease 

 therefore and its association with Big Bud or otherwise the facts will 

 be considered as affecting the outgrowth of laterals and not the failure 

 of the fruit. 



Character of the normal growth in the Black Currant. 



For a correct interpretation of the pathological condition it is 

 necessary to have a correct conception of the normal, and therefore no 

 apology is needed for a description of what is perhaps already familiar 

 to most. 



A strong healthy twig of the current year's growth shows the following 

 arrangement of buds in winter. 



The lowest buds are generally weak and are often wood buds, that is 

 buds having one single growing point surrounded by rudimentary leaves. 

 The rest of the buds up to the terminal are flower buds. They vary in 

 strength but all show the same structure. They consist of a median 

 flower rudiment, made from the typical growing point present early in 

 the summer, and two accessory, weak growing points. 



The terminal bud is a typical but strong wood bud. 



In the subsequent year growth takes place as follows (PI. Ill, Fig. 1). 

 A strong wood growth issues from the terminal bud forming the fruiting 

 wood for the following year and the flower rudiments in the lateral buds 

 unfold and bear fruit. One or both accessory growing points present 

 in the fruit bud make a short spur-like growth and form fruit buds to 

 give fruit the following season. 



The wood buds at the base of the winter shoot remain dormant, make 



