PLANT DISEASE AND THE " VICIOUS CIRCLE." 315 
The simpler organization of plants probably explains why this 
complication of disease is so much less specific than it is in 
zoopathology. Another reason is that in animals every organ is 
fully developed and performs its functions almost to the utmost, while 
in the plant, on the other hand, there are always present the rudiments 
of new organs as well as reservoirs of reserve materials, and each of 
these provisions can assist in making good any failure of functional 
activity. A further explanation may be found in the more intimate 
union of cells in the animals as compared with the plant allowing of 
closer interdependences. 
Apart from these reasons, however, there can be little doubt 
that with the growth of our knowledge of correlations in plants many 
examples of specific circuli vitiosi remain to be discovered. A further 
proof will thus be supplied of the essential unity in the laws governing 
animal and vegetable pathology. 
Lastly, the study of Vicious Circles contributes to scientific horti- 
culture. It should indeed be a cardinal principle of the treatment 
of plant diseases to interrupt injurious circular reactions at the earliest 
possible moment. The smallest help afforded at the right moment 
may arrest the progress of disease and break the sequence of the 
destructive factors. If a beginning is once made, the vis medicatrix 
naturae may once again become operative and complete the processes 
of repair. In the words of a famous therapeutist, Sir Lauder 
Brunton : " We must see where the Circle can best be broken, since 
if we break it at one point we allow recovery to commence/' 
