234 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1918. 



several months. Before it is ready to be made up into dressings, 

 however, it must be sorted over (pi. 3) and then dried. In sort- 

 ing, all foreign material is carefully culled out, and at the same 

 time the moss may be separated into two or more grades. The 

 drying is best accomplished by spreading out the sorted moss in 

 the open air, preferably on drying racks made for the purpose. On 

 account, however, of the obvious difficulties associated with drying 

 large quantities of moss in the open, various methods have been 

 devised for drying it indoors (pi. 4). As soon as it has been 

 properly dried the sphagnum is ready to be made up into dressings. 



SPHAGNUM ABSORBENT DRESSINGS. 



The simplest type of sphagnum absorbent dressing consists of a 

 cloth bag, which is loosely filled with the moss and then sewed up. 

 The bag is made of light weight muslin of close weave, the usual 

 gauze covering being impracticable on account of its open texture, 

 which permits fine particles of moss to work through and cause 

 irritation. This is the type of dressing authorized by the British 

 War Office. A modification, developed by the Canadian Red Cross, 

 embodies the use of an inner envelope of thin Scot paper tissue to 

 contain the sphagnum, thus permitting the use of gauze for the outer 

 covering. The type of pad developed and adopted by the American 

 Red Cross (pi. 4) is essentially similar to the one just mentioned, 

 except that it has a backing of non-absorbent cotton. In favor of 

 the American type of pad, it is urged that it has the advantage of 

 not becoming quickly wet through to the back. In favor of the 

 simpler types it can be said that, besides being less expensive and 

 less complicated to make, these afford better ventilation, thus being 

 cooler and more comfortable. For certain methods of treatment the 

 American type of pad unquestionably is superior, but " for ordinary 

 cases of infected wounds the straight sphagnum pad, made either 

 with a muslin cover or with gauze and tissue, is in every respect 

 equal to the cotton backed pad :" in fact, in many respects, it is 

 better. 1 Full directions for making the different types of sphagnum 

 absorbent pad are given in the papers by Professors Porter and 

 Hotson, already referred to. 



1 This opinion is expressed by Professor Porter in a recent letter to the writer. lie 

 further emphasizes " the especial suitability of the straight sphagnum pad for tropical 

 use and for men who have been burned," as is the case with so many naval casualties. 



