100 THE AMERICAN MONTHLY [Apr 



logical, physiological, pathological and ecological charac- 

 teristics of plants with most satisfactory results. The 

 strength of the formalin solution used for preserving 

 specimens is four parts of the forty per cent solution to 

 one hundred parts of water. Two to three parts to one 

 hundred have been tried, but solutions of this strength 

 have not proved satisfactory. Most of the specimens 

 have been kept in a 4-100 parts solution for five years 

 without renewing, and with the exception of a slight ten- 

 dency to form a precipitate in some of the jars, they are 

 as clear as ever. Formalin solution gives clear white col- 

 orless tissues, whereas the tissues placed in alcohol have 

 invariably turned to a dirty brown. 



Diatoms. — Living diatoms survive for days when stain- 

 ed with methyline blue solution (one in one hundred thou- 

 sand),but the vitality of the cells wanes from the moment 

 the nucleus takes up the stain. 



Plant Histology. — Prof. C. J. Chamberlain gives an 

 admirable series of articles on methods in plant histolo- 

 gy. He treats of the Algae, fresh-water marine, and of 

 the Fungi. Under the Phycomycetes, he briefly discusses 

 Mucor stolonifer, the familiar bread mould, and suggests 

 the following method as a sure and rapid method for ob- 

 taining it : — Place a glass tumbler in a plate of water, 

 put a slice of bread on the tumbler, and cover with a 

 glass jar. To obtain a good series of sporangia the ma- 

 terial should be studied before the sporangia begin to turn 

 black. There are phases in the life-l\istory in the forma- 

 tion of the zygospore, which are rarely seen, and there- 

 fore the writer would be glad to hear from anyone who 

 has met this phase, especially if the information could be 

 accompanied by a few dry zygospores. A very satisfactory 

 study may be made from the living material. Corrosive 

 sublimate (four per cent) in fifty per cent alcohol, used 

 hot, is recommended as a fixing agent. — Knowledge, 



