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but also that the very same species may vary greatly in dif- 

 ferent localities. Growing under certain conditions it may ac- 

 quire that soft, "bushy" habit so desirable in material which is 

 to be used for surgical dressings, while growing under other 

 conditions it will be harsh, stringy, and quite unfit for surgical 

 purposes. Even Sphagnum papillosum exhibits considerable 

 variation in this respect. And this brings up another question. 



Where does the sphagnum grow? In what kinds of habitats does 

 it occur, and in what sections of the country does it develop best? 



When it comes to locating sources of supply for surgical 

 sphagnum, obviously it is not enough to be able merely to recog- 

 nize the sphagnum when you see it. It is not even enough to be 

 able to distinguish surgical from non-surgical material. It is 

 every bit as important to know in what sort of places to look for 

 it, and also what sort of places to steer clear of. 



In general, the sphagnums grow in wet places. Taken as a 

 class they are moisture-loving plants. Considering them from 

 a geographical point of view, it can be said that th^y grow best 

 in regions where the climate is moist the year round, but especi- 

 ally in summer, and where the summers are not too hot. They 

 attain their best development in cool, humid regions, such as 

 Newfoundland, Nova Scotia and New Brunswick, Vancouver 

 Island and western Washington. On the whole, they develop 

 most luxuriantly near the seacoast, particularly along coasts 

 where fogs are frequent. They are better developed northward 

 than southward. This is especially true of Sphagnum papillosum, 

 which has never been found at all south of New Jersey. In the 

 northern regions that I have just mentioned the sphagnums are 

 very widely distributed, occurring not only in swamps but to a 

 considerable extent on uplands as well. Farther south, in regions 

 where the climate is drier and the summers hotter, they are 

 mostly confined to swamps. 



Now in this connection, there is one particular type of swamp 

 that I want to call attention to, and that is the kind of swamp 

 known as a bog. It is in bogs that the sphagnums develop most 

 luxuriantly. Let us consider first the conditions which prevail 

 in southern New England, a region in which the bog type is in 



