March 3, 1899.] 



SCmNGE. 



333 



and these invariably perennials. Bulbs and creep- 

 ing rootstocks occur, but the cespitose habit so 

 common among dry-land plants is entirely absent. 

 Notwithstanding the abundance of climbing 

 woody vinesand bamboo-like Arundinarias which 

 give an aspect of tropical luxuriance, the flora is 

 predominantly boreal in origin. Many northern 

 plants have their southern limit of distribution 

 here, and, on the other hand, several southern 

 types have never been found farther north. 



Mr. William Palmer continued Dr. White's 

 discussion of the physiography, with particular 

 reference to the changes due to human agencies. 

 The vegetation becomes very dense along canals 

 and ditches where formerly the swamp was com- 

 paratively open, as far as undergrowth was con- 

 cerned. These ditching operations have been 

 carried on since the days of George Washing- 

 ton, who spent considerable time in the Dismal 

 Swamp in surveying and managing the work, 

 and who died possessed of $2,000 in stock in 

 the enterprise. 



It was stated that the drainage of the swamp 

 is very intricate, the direction of the current 

 being not infrequently reversed in the same 

 channel. Miocene bivalve shells are found in 

 great abundance near the northern end of 

 the Jericho Ditch. Of existing animals there 

 are thirty mammals, the more prominent of 

 which are deer, opossums and wild cattle. 

 Forty-one species of birds are regular sum- 

 mer residents, with many more transient visi- 

 tors. The most characteristic bird of the swamp 

 is perhaps the Prothonotary Warbler, a rare 

 bird everywhere else, but not uncommon in the 

 swamp. The resident birds and mammals in 

 some instances show distinct characters, by 

 which they may be readily separated from those 

 of the neighboring drier regions, and have con- 

 sequently been described as distinct species 

 or subspecies. Fourteen species of iish are 

 known from the waters of the swamp, although 

 it is believed that none existed in Lake Drum- 

 mond until admitted through the canals. 

 Snakes may be said to be abundant, as Mr. Pal- 

 mer has counted 153 while passing along one of 

 the canals on a warm day. The King Snake is 

 very tame and sometimes climbs into boats, but 

 with no malicious intentions. Four frogs and 

 six turtles were also enumerated. 



In conclusion, Mr. Palmer stated his regret 

 that the opportunity of holding the vicinity of 

 Lake Drummond as a National Park had not 

 been improved before its great natural beauties 

 were so largely destroyed. 



The 302d regular meeting was held February 

 11th, but, owing to the unusually severe and in- 

 clement weather, the attendance was small, and 

 several members who had arranged to continue 

 the discussion of the Great Dismal Swamp were 

 absent. After electing to active membership 

 Dr. Oscar Loew, of Washington, and Lieutenant 

 Wirt Robinson, of New York, the Society 

 voted to postpone the discussion and adjourn. 

 O. F. Cook, 

 Corresponding Secretary. 



CHEMICAL SOCIETY OF WASHINGTON. 



The regular meeting was held on January 

 12, 1899. 



The first paper of the evening was read by 

 Dr. E. A. de Schweinitz, and was entitled 

 ' The Serum Treatment of Some Animal Dis- 

 eases.' 



In this paper the author gave a general re- 

 view of the work begun in 1890 in the study of 

 the substances secreted by the hog cholera and 

 the swine plague germ in relation to immunity. 

 He further pointed out the production of an 

 enzyme by the hog cholera and other allied 

 germs, and their importance in producing in 

 animals immunity from disease. From this 

 point the work was extended to a study of the 

 serum obtained from animals that had been 

 immunized to disease, and this was found to 

 contain an immunizing principle and exerted 

 curative properties upon experimental animals 

 affected with hog cholera and swine plague re- 

 spectively. Following these experiments, prac- 

 tical work has been carried out in the field for 

 several years, with very satisfactory results. 

 The treatment with serum was found to save 

 about 80 per cent, of infected herds, while in 

 those herds not treated which served as checks 

 the loss from disease was over 80 per cent. 



In practical work in the field it is diflScult to 

 decide often whether the animals are suffering 

 from either hog cholera or swine plague alone 

 or both of these diseases. To overcome this 

 difBculty it has appeared advisable to use a 



