THINGS ESSENTIAL TO BOTANICAL TEACHING 47 



impose hard work at a time when the teacher should 

 be resting, is not so great as it seems. The change 

 in occupation, surroundings, and companions brings so 

 much relief in itself, that the work is less felt ; and 

 besides, if the learner's spirit is of the right sort, and 

 the teaching is of the true quality, the pleasure of it 

 all should go far to lighten the labor. In my own ex- 

 perience, too, I have found that there is more rest in 

 change of occupation than in absence of it. Perhaps 

 the mind is in this like the soil, that it does not need 

 to lie fallow, but can continue to bear without exhaus- 

 tion if given a wise rotation of crops. Of all the 

 excellent summer schools in this country, however, 

 that which is in my opinion the most profitable to 

 the teacher is the Marine Biological Laboratory at 

 Wood's Roll, Massachusetts, which belongs to no single 

 institution, but to them all. Here, in addition to the 

 excellent courses and the great facilities, there are 

 opportunities unrivalled in this country for that ac- 

 quaintance with co-workers and specialists, and that 

 scientific atmosphere, which are worth to the teacher 

 as much as the instruction itself. 



After summer schools, and long after, comes study 

 by one's self. But this to be efficient should be actual 

 practical laboratory study done under the advice and 

 criticism of some specialist. Study without guidance 

 is sure to be full of gaps and bad in its proportions. 

 Correspondence courses, which some institutions offer, 



