2224 



Journal of Applied Microscopy 



The Technique of Biological Projection and Anesthesia of 



Animals. 



COPVKK.HTED. 



XII. THE ANESTHESIA OF ANIMALS.— Continued. 



MOLLUSCA : Snails. — Specimens with transparent shells may be used for 

 the study of the heart beat and various morphological details, while both small 

 and medium sized snails may be employed when ciliary action is to be looked 

 for on the surface of the tentacles and foot. 



Place the animals in a watch-glass in water enough to cover them and add 

 one-half its volume of one per cent, chloretone solution. Some species require 

 an increased amount of the anesthetic up to equal volumes with the water. 



Polyzoa. — The sensitiveness of these delicate and beautiful animals makes 

 their careful study in the live state under hand lens or compound microscope a 



difficult task, unless some anesthetic 

 suited to their peculiarities is em- 

 ployed. Chloretone has served ad- 

 mirably for the species thus far tested. 

 Place one or more specimens in a 

 watch-glass with water enough to 

 cover them and allow them to stand 

 quietly until the tentacles are ex- 

 panded. Add one per cent, chlore- 

 tone solution drop by drop from a 

 pipette, watching the effect until the 

 desired degree of anesthesia has been 

 attained. If at any time too much 

 chloretone has been added, water may 

 be dropped into the watch-glass to 

 dilute the solution. The tentacles, 

 lophophore, and general morpholog- 

 ical details require a less complete 

 degree of anesthesia for their study 

 than do the cilia which thickly clothe 

 the tentacles. To study the various 

 degrees of activity of the cilia frofn 

 the normal rapid motion, during which the individual cilia are not visible, 

 through the stage in which the movements are slower and the cilia appear to 

 act in groups, to the final stage of activity which is characterized by slow and 

 irregular motions of each cilium, it is necessary to add chloretone solution drop 

 by drop while the animals are under the microscope. Before the last stage is 

 reached the tentacles become distorted by an angular bend. 



Vertebrata : Goldfish. — Small goldfish, /. e., from two to three inches 

 long, are among the most desirable, if not the best, vertebrates in which to 



Fig. 7. — Optical Section of Head and Prothorax 

 of Nymph of Dragon Fly. Photographed 

 from screen, as studied by a class, to dem- 

 onstrate the usefulness of projection methods 

 in teaching the anatomy of live animals and 

 the value of anesthesia. 



