98 CONCLUDING BEMARKS. 



in different years and different localities the proportions in which 

 the constituents of ergot occur present certain variations. 



If, on the other hand, an approximate analysis is not required, 

 but in its stead a fairly accurate comparison of specimens gathered 

 in different fields, then it must be borne in mind that only certain 

 practic9,lly valuable constituents have to be taken into account, for 

 the estiination of which more accurate methods may not unfre- 

 quently be devised. This we are generally able to accomplish, 

 for we are in a position to elaborate the necessary mode of treat- 

 ment, to determine the extent of the errors involved, and the 

 corrections to be made for them, and to make several estimations 

 frord the same material from which a mean may be calculated. 



