1852 Journal of Applied Microscopy 



water, in which it like lead chloride is soluble, yields well formed cubes. 

 In the presence of chlorides of antimony and bismuth complex chlorides of 

 low solubility are sometimes formed, against which the analyst should be on his 

 guard. 



Exercises for Practice. 



To a drop of a concentrated solution of Pb(N03)2 add a drop of dilute hydro- 

 chloric acid in the manner described above. Make several other preparations 

 varying the concentration of the test drops. 



Recrystallize a preparation of PbCU by heating to boiling with a large drop 

 of water. 



Recrystallize a preparation of PbC^ in the presence of NaCl, another in the 

 presence of KCl, of NH^Cl, of CsCl. 



Test a solution of Pb and Sb. Then one of Pb and Bi. Then one contain- 

 ing all three elements. 



To a preparation of PbClj add a drop of NH^OH. 

 Cornell University. E. M. ChamOT. 



LABORATORY OUTLINES. 



For the Elementary Study of Plant Structures and Functions from 

 the Standpoint of Evolution. 



IX. Slivie Moulds (continued). 



(e) Ama'ha Sp. Class, Rhizopoda. Order, Amoebina. 



If the student has not studied the Amoeba in a general course in zoology, it 

 should be taken up at this point, since the amoeboid form probably represents 

 the most primitive type of cell with which we have to deal. Amoebas can 

 generally be found in the ooze at the bottom of ponds and creeks. To obtain 

 Amoebas in large quantities, pack a glass jar rather tightly with Ceratophyllum 

 or with pond lily leaves, and cover with water. The dish should be covered 

 up. After a week or two, when the plants begin to decay, Amoebas will usually 

 be abundant. 



1. Scrape off some of the sediment from the Ceratophyllum leaflets and 

 mount in water together with some of the brown scum present at this time in the 

 jar. Under high power search for transparent, naked cells of irregular shape, 

 which are slowly changing in outline by thrusting out pseudopodia. Sketch the 

 outline of an individual six times successively, at intervals of ten seconds. 



2. Describe the amoeboid movement of the animal, and the formation of 

 the pseudopodia. 



.3. Make a careful diagramatic drawing of a large Amoeba, showing the outer 

 limiting layer (ectosarc), the inner more fluid granular part (endosarc), the 

 nucleus (if distinguishable), the contractile vacuole, and the various ingested 

 foreign bodies, as diatoms, desmids, etc. 



