1438 Journal of Applied Microscopy 



give a view of the structure, development and relationship of all the great groups 

 of Algae and Fungi. The lack of lectures is compensated for by assigned read- 

 ings and the study of a larger number of types. As soon as a lesson is com- 

 pleted, it is sent to the instructor, who returns it with corrections and suggestions. 



Three courses in botany. (1) General Morphology of the Algae and Fungi, 

 (2) General Morphology of the Ikyophytes and I^teridophytes. and (3) General 

 Morphology of the Gymnosperms and Angiosperms, have been thoroughly tested 

 by the writer, nearly a hundred students having taken the work. The results 

 are surprising. Many students after taking one or more of these courses by cor- 

 respondence have come to the university for further work, and have not only 

 been able to hold their own in classes with students who had done the previous 

 work in residence, but, on the whole, have shown a more thorough preparation. 



However, it must not be inferred that correspondence work is preferable to 

 residence w^ork, for such is not the case. The explanation is to be sought in the 

 fact that those who have sufficient interest and determination to carry on a course 

 by correspondence are willing to devote more time and effort than can be required 

 of the average university student. It is particularly noticeable that correspond- 

 ence students, when they come for resident work, are more independent and ask 

 fewer thoughtless questions than those who have always had an instructor at the 

 elbow. Several who have laid the foundation for morphological work by corres- 

 pondence have subsequently come to the university for research work, and have 

 published excellent papers, and two have even taken the doctor's degree, with 

 botany as the major subject. 



After the success of these courses became evident, a course in histological 

 technique, preeminently a laboratory course, was offered and has proved a suc- 

 cess. Work in the newer, but very popular field of Ecology, is also being con- 

 ducted satisfactorily by correspondence. 



In looking over the list of those who have studied botany by correspondence, 

 it is interesting to note that, aside from the teachers and students who form the 

 great majority, there are also lawyers, business men, clerks and artisans, who 

 have found time to improve themselves in their chosen subject. 



The success which has attended the correspondence work in botany sug- 

 gests that in other sciences also those laboratory courses which do not require 

 very expensive apparatus may be conducted by this method. 

 University of Chicago. ClIARLES J. ChamI'.ERLAIN. 



Dr. W. IUjrck, of the Royal Academy of Sciences of Amsterdam, has re- 

 cently published some observations bearing upon the subject of the prevention 

 of hybridisation in plants. His experiments showed that certain chemical sub- 

 stances act very differently on the pollen of different plants. Levulose in small 

 quantities greatly accelerates the growth of pollen tubes in some plants, while in 

 others the pollen grains are caused to burst. Saccharose and dextrose produce 

 different effects than levulose. According to the author's interpretation these 

 results would indicate the possibility that the stigmatic secretion of a given 

 species contains substances which promote the emission of pollen tubes in that 

 species, but prevent the growth of pollen from other species. — Natiire^\\ 1656. 



