8 



conditions are present may remain in either the humin and 

 ulmin or the acid stage for so long a time as to cause 

 serious inconvenience to growing crops* Again when a 

 soil has been persistently cropped with the same genus of 

 plant, certain ingredients in the soil are exhausted sooner 

 than others) and if this condition is not discovered and 

 attended to> all soi'ts of disasters may result. However 

 rich the soil may be in other respects, the absence of a 

 sufficient proportion of a special ingredient; or constituent, 

 will nullify all efforts aimed at improvement, until such 

 abnormal condition is counteracted. Rotation of crops has 

 been instituted in order to prevent such exhaustion > and the 

 benefits derivable from the institution of fallows have been 

 long apparent even to the uneducated native. It is a known 

 fact that the potato disease is favored, and even probably 

 induced^ by a persistent cultivation of that plant on the same 

 soil for a number of years consecutively - in fact upon a 

 " potato-sick soil.," Strict attention to the principles of the 

 rotation of crops is the only remedyjand if such is impossible, 

 beneficial results are even likely to be produced by a 

 careful and systematic change not only of seed but of the 

 variety. 



Mushrooms and fungi are a very .low order of plant 

 and do not grow on vegetable matter which has passed 

 through the ultimate process of decomposition, but seem to 

 flourish under circumstances favoring the maintenance of a 

 peculiar intermediate stage of decomposition which is favor- 

 able to their existence and development ; and it appears 

 that this particular and requisite phase may bo either pro- 

 longed or shortened by chemical applications, and mechanical 

 operations. Now we arrive at a conclusion that the undue 

 exhaustion of individual ingredients of a soil and faulty me- 

 chanical condition of such soil are calculated to induce, or 

 favor, certain abnormal conditions an4 that at particular 



