APPENDIX 519 



mature spermaries of Chara) may be crushed beneath it and 

 their parts scattered, and dissociated for study, b) Many 

 objects not too flat may be turned over, or rolled into 

 new positions for observation, by pushing on the edge of 

 the cover. 



8. Drop Cultures for germinating spores, etc., are madia 

 upon cover glasses. A drop of culture fluid is placed on the 

 middle of a cover which is then inverted and laid over the 

 open well in a hollow ground slide, or over a ring of thick 

 wet blotting paper, where it hangs suspended in the center. 

 The slide is then kept under proper conditions in a moist 

 chamber of some sort, and is replaced on the stage of the 

 microscope for examination at any time without distur- 

 bance of the culture. 



On the dissecting of any of the larger animals . 



1. Learn to handle your tools, forceps, scissors, scalpel 

 and needles, and to depend on them for results; hacking to 

 pieces is not dissecting. 



2. Open the body cavity where access is easiest and 

 damage to internal significant parts is least likely to occur. 

 This will be the dorsal side in worms and arthropods , and the 

 ventral, in vertebrates. 



3. If delicate parts are to be seen, immerse under water, 

 which will float them into better view. 



4. Be careful not to cut into any organ whose contents 

 will roil the water and hinder observation. 



5. Fully expose the organs to be observed by pinning 

 the flaps of the body wall out of the way as by pinning them 

 to the bottom of the dissecting tray. 



6. Know what you are looking for, but do not be too 

 easily convinced that you have seen it. 



