274 Proceedings of Royal Society of Edinburgh. [sess. 
Lawrence. Severe malarial fever is found at Fort Gratiot, Detroit 
and Plymouth, on the United States side of the Lake ; and at 
Amkurstbury, Fort Maldon, and Sandwich, on the Canadian side. 
On the northern side of Lake Ontario malaria extends from Hamilton 
to Kingston, and up the ridge of hills which runs along the shore 
from Burlington to the mouth of the Trent, attaining in some places 
an altitude of 600 feet. Endemic malaria extends also to the north- 
western parts of the State of Hew York, although there are many 
localities now free from fever. It is most frequently met with along 
the banks of the Hudson and on a narrow strip of coast. During 
recent years the disease has increased in the mountain districts of 
New York and also in Pennsylvania. In the New England States 
the disease is endemic at only a few points, and it is not endemic in 
the greater part of British North America. Malaria, as an epidemic, 
is met with on the banks of the St Lawrence and its tributaries, and 
on Lake St Peter, as well as at Montreal and Quebec, and at various 
coast places, such as Halifax (N.S.) and Miquelon (N.F.). In 
Nova Scotia (except at Halifax), in New Brunswick, and in Green- 
land, the disease is quite unknown. In western North America the 
limit of malaria reaches somewhat higher latitudes. It is met with 
chiefly on the slopes and valleys of the Bocky Mountains 
and in the territories of Wyoming, Utah, and Colorado. In Cali- 
fornia there are considerable malarial regions, especially up the 
valleys of the Sacramento and San Joaquin, and in the inland 
southern part of the State of Arizona. 
The incidence of malaria throughout the world has been very well 
summarised by Mr W. North, whose classification I will quote.* 
First Category. Highest Degree of Intensity. 
Class I. Senegal; Coasts of Gulf of Guinea; West Coast of 
Africa, as far as the 20th parallel of S. latitude ; Madagascar ; the 
Guianas. 
Class II. India ; Cochin-China ; Ceylon ; Afghanistan ; Burmah ; 
Siam ; the whole of the Malay and Philippine Archipelago ; New 
Guinea ; Nubia ; parts of Abyssinia and the Soudan, and Central 
America. 
* See Nineteenth Century , June 1889, p. 867. 
