1899] DISTURBING THE BALANCE OF NATURE 311 



trees were cleared, and at present the scales are being reared to 

 preserve the lady-bugs in case of another outbreak." In 1897, in 

 Portugal, the experience of the United States was successfully repeated. 



From Dr. Blackford's article we may take one other example : 

 " In many of the rivers of Brazil a plant grows that is called the 

 Water Hyacinth. It is very ornamental, and a few years ago a land- 

 owner on the St. John's Eiver, in Florida, procured a small number 

 for a pond on his estate. They increased rapidly and filled up the 

 pond, whereupon the owner had them gathered up and thrown into 

 the river. The experiment was unfortunate. Free from natural 

 enemies, the hyacinths have flourished, so that on many streams 

 navigation is practically impossible. From shore to shore there 

 spreads an impenetrable sheet of vegetation that entangles paddles, 

 oars, or propellers, and arrests all manner of refuse that should go to 

 the sea. From time to time bodies of this growth become detached 

 and drift down until salt water is reached, when the plants die and 

 are cast ashore in putrescent heaps. A natural enemy has been 

 sought, but as yet no appreciable result has been accomplished. In 

 Brazil a small red spider lives on the hyacinths, and is said to be 

 injurious to it. This spider has been introduced into Florida, but no 

 effect has been perceived." 



In conclusion, the theoretical interest of these cases is all very 

 well, but " things are in the saddle," and practical considerations force 

 themselves upon us. Therefore we have pleasure in quoting the last 

 paragraph of Mr. Palmer's article. " Congress should take steps 

 promptly to protect Hawaii and Puerto Eico against further intro- 

 duction of noxious species, and to prevent the mongoose from being 

 brought into the United States. The introduction of exotic mammals 

 and birds should be restricted by law, and .should be under the control 

 of the U.S. Department of Agriculture. The wild rabbit, the mon- 

 goose, the flying foxes, and the mina of the Old World, should be 

 rigidly excluded ; and species of doubtful value, such as the starling, 

 skylark, kohlmeise, and blackbird, should be imported with the greatest 

 care, and only in places where they can be controlled in case they 

 prove injurious." 



Notes on American Mammals. 



Mr. D. G-. Elliot, so well known from his magnificent illustrated 

 monographs of various groups of animals, as well as from his less pre- 

 tentious handbooks of North American game and water birds, has 

 recently turned his attention to faunistic work. The results of his 

 labours have been presented to the public in the " Publications of the 

 Field Columbian Museum," and comprise the mammalian fauna of the 

 Olympic mountains, notes on certain reptiles and batrachians from the 



