ZOOLOGY AND B0TA3SY, MICKOSCOPY, ETC. 331 



might be introduced. An example of importation is afforded by the 

 recently-discovered onion smut, which has been known as a bad disease 

 in the States for fifty years, but has only now appeared in England. 

 It is somewhat disappointing to find only a few diseases fully described, 

 but no single volume could contain all that one wants to know. 



The " Laboratory Exercises " should prove very helpful to student 

 and teacher alike. Good technique and the proper use of instruments 

 are of great value in research work, and gratitude is due to the writer 

 who thus places the results of his experience at the disposal of others. 

 In the appendices there is detailed information on aspects of plant 

 pathology that supplements the main body of the work. They indicate 

 the methods of treating special classes of fungi. 



We cordially recommend Harshberger's text-book to mycological 

 students ; they will find much to interest and instruct, probably also 

 something with which they will disagree. The author is apt to dogmatize 

 on subjects such as cytology and symbiosis, which are still debated 

 points. A. L. S. 



