278 APPENDIX. 



DIRECTIONS FOR THE PREPARATION OF MATERIAL FOR 



STUDY. 



The following directions are placed in the Appendix, because it 

 has not been found practical to have them carried out by beginners 

 in zoology. They are therefore intended for the teacher or for his 

 assistants. Anticipating that this book will fall into the hands of 

 some teachers who are not at all familiar with zoological laboratory 

 methods, a few of the simplest are given in the following notes, with 

 much detail which would be unnecessary were all who are called 

 upon to teach zoology fitted for the task by a laboratory training. 

 If the methods given below are not in all cases the best methods 

 known to science, they are believed to be the best that can be well 

 applied with such equipment as is usually provided for elementary 

 work in zoology. 



I. On finding Amoeba. The amoeba lives in the superficial ooze of 

 ponds and ditches everywhere, but it is not often very abundant. It 

 may be most easily obtained from shallow pools. To get it, scrape up 

 the superficial ooze from the bottom of the pool, avoiding the mud that 

 underlies the ooze, and place in a shallow dish with water. Allow the 

 ooze to stand undisturbed for a day or two. The amoebas will then 

 have come to the top of the ooze, whence they may be taken up with 

 a dropping tube. Place small drops water, ooze, sediment and all 

 on separate glass slips, and cover each with a thin glass cover slip. 

 The sediment in the drops will prevent the cover slips from crushing 

 the amoebas. The slips may then be searched quite rapidly, and 

 amcebas recognized, with a power of 250 diameters. A practiced eye 

 will recognize them with much lower power ; but the eye that does 

 not know just what to look for may pass them over even with this 

 amount of magnification. Higher powers cannot be used in searching 

 the field over without too great expenditure of time. The beginner's 

 trouble comes from the unlikeness of the clear jelly-like mass spread- 

 ing over the glass slip to anything commonly denoted by the term 

 "animal." 



Amcebas are found also in the slime that covers the stems and 

 leaves of some submerged plants, and in the thin scum on the surface 

 of the water. The slime or the scum may be collected, and treated 

 in the same way as the ooze mentioned in the foregoing paragraph. 



It is well to make separate collections from several places, to insure 

 finding amoebas. 



