258 Mary Davies Swartz, 



(7) particularly recommends Iceland moss {Cetraria islandica) as a 

 diet for consumptives, as "it seems to be both extremely nutritious 

 and very easy of digestion, though of course, only capable of use as a 

 substitute for starchy matters." In regard to Irish moss {Chondrus 

 crispiis), he is a little more uncertain. "It is much used for invalids, 

 especially in cases of consumption, but with doubtful advantage when 

 substituted for more nutritious food." Schneider (21) says of Ice- 

 land moss: "Inhabitants of Iceland, Norway, and Sweden mixed this 

 lichen with various cereals and mashed potatoes, from which an un- 

 commonly healthful bread was prepared." Until the matter has been 

 thoroughly investigated, we must suspend our judgment as to the ac- 

 curacy of such statements. After a few metabolism experiments, 

 Oshima (15) far more conservatively remarks concernmg the algae of 

 Japan: "Their actual value doubtless depends in considerable measure 

 upon the mineral salts they contain." 



In view of the scarcity of any scientific investigations as to the be- 

 havior of all these substances in the body, further experiments upon 

 their nature and digestibility seem highly desirable, since they are not 

 only widely distributed, and already form a considerable portion of 

 the diet of many persons; but because, if they possess any real nutri- 

 tive value, a wider use of such comparatively cheap materials would 

 be an economic advantage; and because, under the prevailing notions 

 as to their food value, they are sometimes relied upon as a source of 

 nutriment in diseases (as diabetes) where the character of the diet is 

 particularly important. The present work has been undertaken to 

 throw some light on this interesting subject. A survey of the litera- 

 ture shows that even the chemical nature of many of these algae has 

 scarcely been investigated; and if this were known, we should still be 

 under the necessity of studying their behavior in the animal body, 

 for it is impossible to tell from chemical analysis alone whether a 

 given substance will or will not prove digestible, as Rubner has long 

 since warned us. 



