and Laboratory Methods. "-^^TS 



above, and add one per cent, chloretone solution drop by drop until the desired 

 condition is secured. With this species, as with nearly all others, which are 

 readily brought under the influence of the anesthetic, it is best to return the ani- 

 mals to clear water as soon as their study has been completed, as repeated appli- 

 cations of the drug are less fatal than is a single long continued treatment. For 

 example, branchipus was to be projected before two classes and was treated as 

 follows: first, shown in normal activity; second, without removing it from the 

 projection microscope chloretone was added and the gradual change to the state 

 of anesthesia was -observed ; third, under higher power objective a study was 

 made of its anatomy and the functional activity of some of its organs ; 

 fourth, it was returned to clear water and soon resumed its normal activity, after 

 which the same series of operations was repeated for the second class. 



Note. — Articles I-VII of this series were devoted to the consideration of 

 available lights for micro-projection, the necessary apparatus and its adjustment ; 

 articles VIII-XIV describe the methods of anesthetizing typical animals 

 with chloretone ; and the remaining articles will deal with the technique of 

 mounting live plants and animals in the different forms of cells and their man- 

 ipulation on the projection microscope. Among the hundreds of species which 

 might be used, a few must be selected to illustrate typical methods. The 

 author desires to make the work as generally useful and helpful as possible, and, 

 to this end, would be pleased to receive from those who are using the projection 

 microscope, or are planning to use it, lists of the live objects which they wish 

 to project, and these lists will be utilized in the selection of types to be considered 

 in the articles which are to follow. Also, all who have inquiries in reference to 

 difficulties which they have experienced in carrying out the directions published 

 in the preceding articles are invited to state them in letters to the author and 

 they will be given attention. Address correspondence to No. 5715 Monroe 

 avenue, Chicago, 111. A. H. Cole, 



University of Chicago. 



Laboratory Outlines for the Elementary Study of Plant 



Structures and Functions from the Standpoint 



of Evolution. 



THE HIGHER FUNGI AND LICHENS. 



XXXI. Saciharomyces cerevisia Meyen. Beer and Bread Yeast. 



Class, Ascomycetes. Order, Saccharomycetales. Family, Saccharomycetaceae. 



To obtain yeast plants in active, vegetative condition, take a piece of ordi- 

 nary dry yeast cake and put it in a glass of water containing a small amount of 

 sugar. Keep over night in a warm place. 



1. Mount some of the water contaning yeast plants and study under high 

 power. Draw several of the large oval cells present ; also a short, branched 

 filament of cells. 



'1. Notice the formation of new cells by process of budding. Draw a num- 

 ber of cells showing the several stages in the formation of a daughter cell. 



