45° The Ohio Naturalist. [Vol. VI, No. 3, 



disappearing. And last, but not least, the influence on general 

 health is a grave consideration. 



But to come back to mollusks. Of late years, the shell and 

 pearl hunters have come, and killed our mussels, where there still 

 were any, by the millions, in rivers and creeks. In many places 

 they have been nearly exterminated, and only the naturalists 

 deplore the fact. 



What can we do? When Hebra, the great dermatologist at 

 the University of Vienna, presenting to his students a peculiar!}^ 

 malignant case of a skin disease, asked the practicing student 

 what could be done for the patient, and the young doctor could 

 only shake his head and stand silent, "well, we will have him 

 photographed," Professor Hebra would say. This is about our 

 position. In the first place, we can record the fact, and deplore 

 it. In the second place, we can take a careful inventory of what 

 is still left. And that we should do, energetically: work up the 

 muollsca in the rivers, creeks, springs, swamps, in the forests 

 and copses left, and have them in our records and collections, 

 for future generations to look at. In the third place, we 

 might find some creek here or there, or part of such, preserve it 

 in as natural conditions as possible, eventually with additional 

 ponds, and try to preserve in it, and on its banks, such mollusks 

 as are threatened with extermination. This sounds utterly 

 fantastic ! and yet the time may come when such a plan may be 

 considered. 



And in the fourth place, and above all, let us unite forces 

 with government oflicials, and anybody who will try to put an 

 end to the reckless deforestation of our land, and the reckless 

 contamination of our waters with factory and city refuse. 

 Already it is much too late, but still much can be accomplished. 

 I believe it is not below the dignity of the Academy and its 

 members to direct the^r attention to these eminently important 

 tasks and to do all in their power to promote them. 



I know well that I go far beyond my scope with these last 

 remarks, but these matters were so much no my mind that I 

 could not help at least touching them, and I hope to be excused 

 for doing so, even if the topic "mollusks" is only incidental 

 to them. 



ADDITIONAL OBSERVATIONS ON SELF-PRUNING. 



John H. Schaffner. 



In 1901, Mr. Tyler and the writer published some notes, in 

 The Ohio Naturalist, on the self-pruning habits of a consid- 

 erable number of trees and shru1:)s. The list has been extended 

 from time to time by the writer, the work being confined neces- 

 sarily to the common woody plants of our region. It is gratify- 



