34 COMMON POND SCUM. 



gathering will answer for the present study, as 5. 

 longata Vauch., S. majuscula Kiitz., and similar kinds 

 have been kept in mind as well as 5. quinina in drawing 

 up the outline for laboratory work. 



Spirogyra may be grown in the laboratory, and the 

 vegetative condition kept always at hand, by using a 

 rather deep vessel with opaque sides, and occasionally 

 dropping in a small piece of peat which has been 

 thoroughly boiled and afterward saturated with the 

 following nutritive solution: 1,000 cc. of water, i gm. 

 potassic nitrate, .5 gm. sodic chloride, .5 gm. calcic sul- 

 phate, .5 gm. magnesic sulphate, and .5 gm. finely pul- 

 verized calcic phosphate. 1 The last, for which burned 

 bone may be used, is only sparingly soluble. If run- 

 ning water can be conducted through the jar contain- 

 ing Spirogyra, so that the water in it may be slowly 

 changed, the peat and nutritive solution can be dis- 

 pensed with. The fruiting plant may be preserved 

 in fair condition for study in a fluid of equal parts of 

 glycerine and alcohol. 



The requisites for study are thrifty growing plants ; 

 fruiting plants, fresh if possible ; alcohol ; glycerine ; 

 and iodine. 



LABORATORY WORK. 

 GROSS ANATOMY. 



A. GENERAL CHARACTERS. Notice 

 i. The yellow-green color as seen in mass. 



1 Sachs, Vorlesungen liber Pflanzen-Physiologie, p. 342. 



