154 Scientific Intelligence. 



group is always a difficult matter, for both sporangia and cysto- 

 carps are oiten wanting, and the habit of the thallus depends 

 upon the place of growth and the surroundings. Furthermore, 

 the older descriptions were frequently very vague and incom- 

 plete. The author has reduced a number of the species of previ- 

 ous Scandinavian writers to synonyms, but has created a number 

 of new species, so that we now have the surprising number of 

 thirty-nine species in the region studied. Apart from Greenland 

 species, the North American species noted are L. fruticulosum 

 (Ktitz) Fosl., and L. colliculosum Fosl., to which are referred the 

 L. fasciculatum of Farlow's Marine Algaa of New England ; 

 L. flabellatum Rosenv., to which is doubtfully referred a sterile 

 specimen found by Collins in Maine; L. compactum Kjellm., the 

 common New England form usually referred to L. polymorphum; 

 L. evanescens Fosl., collected by Collins at Marblehead, Mass. ; 

 L. lsevigatum Fosl., from Kennebunkport, Me., Collins; and 

 L. Stromfeltii Fosl., and L. Lenormandi (Phil.) Fosl., to which is 

 referred in part the Melobesia Lenormandi of Farlow's Marine 

 Algae of New England. The habits of the different species are 

 given in twenty-three good photo-lithographic plates. The mono- 

 graph closes with a short chapter on Fossil Lithothamnia. 



w. G. F. 



IY. Miscellaneous Scientific Intelligence. 



1. The composition of expired air and its effects upon animal 

 life; by J. S. Billings, M. D., S. Weir Mitchell, M. D., and 

 D. H. Bergey, M. D. — A memoir bearing the above title has 

 been recently issued in the series of Smithsonian Contributions to 

 Knowledge, No. 989. It skives the result of investigations carried 

 on under a grant Irom the Hodgkins Fund of the Smithsonian 

 Institution, for the purposes of determining the nature of the 

 peculiar substances of organic origin contained in the air expired 

 by human beings, with special reference to tlae practical applica- 

 tion of the results obtained to problems of ventilation of inhab- 

 ited rooms. The conclusions contain so much of general interest 

 that they are printed here in full : 



I. The results obtained in this research indicate that in air 

 expired by healthy mice, sparrows, rabbits, guinea-pigs, or men, 

 there is no peculiar organic matter which is poisonous to the ani- 

 mals mentioned (excluding man), or which tends to produce in 

 these animals any special form of disease. The injurious effects 

 of such air observed appeared to be due entirely to the diminu- 

 tion of oxygen, or the increase of carbonic acid, or to a combina- 

 tion of these two factors. They also make it very improbable 

 that the minute quantity of organic matter contained in the air 

 expired from human luugs has any deleterious influence upon men 

 who inhale it in ordinary rooms, and hence it is probably unnec- 

 essary to take this factor into account in providing for the ven- 

 tilation of such rooms. 



