Mr.  William  Carrutliers. 
11 
Some  injuries  are  due  to  physical  causes,  such  as  excessive 
or  insufficient  moisture,  severe  cold,  lightning,  and  furnace 
fumes.  In  the  specimens  submitted  these  causes  were  ex- 
plained and  suggestions  given  for  treatment. 
Parasitism  of  Flowering  Plants. 
The  majority  of  injuries  are  caused  by  the  attacks  of  other 
plants,  which  obtain  the  whole  or  part  of  their  food  as  parasites. 
Dodder  and  broom-rape  feed  entirely  on  clover  and  ultimately 
destroy  it.  The  mistletoe  also  gets  all  its  food  from  the  trees 
on  which  it  grows.  Yellow  rattle  and  eyebright  obtain  part  of 
their  food  from  the  roots  of  the  host-plant,  but  at  the  same 
time  they  manufacture  a part  of  their  food  in  their  green 
leaves,  which  are  absent  in  the  other  parasites  named.  These 
have  been  described  and  figured  in  the  Journal,  and  methods 
of  treatment  have  been  given. 
Parasitism  op  Fungi. 
The  greater  number  of  diseases  affecting  plants,  and  the 
most  serious,  are  caused  by  parasitic  fungi.  These  have  been 
investigated,  and  many  have  been  cultivated  in  the  laboratory 
to  obtain  the  characters  by  which  they  are  distinguished. 
Information  has  been  given  to  members  of  the  Society,  and 
in  many  cases  published  in  the  Journal,  about  attacks  on  forest 
trees,  as  the  canker  in  larch,  injuries  to  oak,  beech,  and  other 
trees ; attacks  on  orchard  trees,  like  the  serious  one  on  the  Kent 
cherry  trees,  the  different  diseases  of  apples,  pears,  plums,  &c., 
the  American  blight  of  the  gooseberry,  and  the  diseases  attack- 
ing fruit  trees  in  houses,  also  cucumbers  and  tomatoes.  The 
chief  work,  however,  has  been  with  farm  crops.  The  various 
maladies  that  injure  cereals  and  grasses  have  been  investigated 
and  fully  described.  The  so-called  “ clover  sickness  ” was 
traced  to  its  cause,  and  the  result  published  in  the  annual 
reports,  and  more  exhaustively  in  a separate  memoir  by 
Mr.  H.  T.  Giissow,  laboratory  assistant,  published  in  the 
Journal  for  1903,  page  376.  The  various  maladies  of  the  potato 
have  received  much  attention.  In  connection  with  the  prize 
offered  in  1874  for  disease-proof  potatoes  by  the  late  Lord 
Cathcart,  when  President  of  the  Society,  the  Botanist  visited 
the  twenty  localities  in  Britain  and  Ireland  where  the  tests 
were  made,  and  prepared  a report  upon  these  trials  and  the 
result  of  the  competition.  A wall  diagram  of  the  potato 
disease,  showing  its  different  stages,  with  descriptive  letterpress 
and  suggestions  for  dealing  with  it,  was  published  by  the 
Society,  and  copies  were  freely  distributed  throughout  Ireland 
by  the  Land  Commission.  Several  other  diseases  attacking  the 
potato  have  been  investigated,  and  descriptions  and  illustrations 
