20 EXPERIMENTAL EQUIPMENT AND PROCEDURES 



Eastern Gardens - Kissena Blvd. & Rose Avenue, Flushing, L.I. , N. Y. 



Everglades Aquatic Nurseries - 706 Plaza Place, Tampa, Florida. 



Grassy Forks Goldfish Hatchery - Martinsville, Indiana. 



Japanese Goldfish Hatchery - North Branch, New Jersey. 



Metal Frame Aquarium Company - Bloomfield Ave. , Pine Brook, New Jersey. 



Nassau Pet Shop -129 Nassau Street, New York City. 



Tricker, William - Brookside Avenue, Saddle River, New Jersey or Rainbow Terrace - 



Independence, Ohio. 

 U. S. Bureau of Fisheries - Washington, D. C. 

 Wurst, C. - 3843 Frankford Avenue, Philadelphia, Pa. 



(dried salmon and ant eggs, and flies for food) 



AMPHIBIA 



(Adults as well as eggs may be secured from most of the following) 



Carribean Biological Laboratories - Biloxi, Miss. 



Everglades Aquatic Nurseries - 706 Plaza Place, Tampa, Florida. (Hyla only) 



Fletcher, O. K. , Jr. , - Biol. Dept. , Univ. Georgia, Athens, Georgia. 



Hazen, J. M. , - Alburgh, Vermont. 



LeRoy, A. - Alberg, Vermont. 



Louisiana Frog Company - Rayne, La. (Rana catesbiana, clamitans, pipiens, spheno- 



cephala) 

 Marine Biological Laboratory - Woods Hole, Mass. 



HISTOLOGICAL HINTS FOR EGGS AND EMBRYOS 



INTRODUCTION 



Satisfactory slides of embryonic material are difficult to obtain. This is true of chorio- 

 nated and yolk-laden fish eggs as well as the early stages of amphibian development. 

 The essential steps are the removal of membranes, proper fixation, incomplete dehydra- 

 tion, and short embedding in wax-paraffin mixtures, to avoid brittleness and cracking. 



ANESTHETICS 



In general, anesthetics are not necessary when eggs or embryos are to be fixed immedi- 

 ately. Occasionally it is desirable to fix an embryo in a certain position, or to reduce 

 body movements during fixation, when anesthesia is in order. 



a. MS-222 : This imported poison is the most satisfactory anesthetic available, 

 used in 1/3000 concentration either in Standard (Holtfreter ' s) Solution, Spring 

 Water, or Locke's solution (for chick embryos). The embryos are immobilized 

 in about 1 minute and, after return to normal medium, recover in about 10 min- 

 utes without ill effects. Must be used fresh. 



b. Chloretone : Generally 0. 5% concentration in whatever medium the embryo is 

 accustomed, will give slow but quite satisfactory anesthesia. 



c. Magnesium sulphate : (Epsom salts) Simply drop a few crystals into small vol- 

 ume of water containing the embryo and await immobilization. 



d. Cyanide : KCN 1/1000 in salt solutions acts as an anesthetic. Must avoid anoxia. 



e. Ether and chloroform : These volatile anesthetics are for air breathing forms; 

 hence will find little use with embryonic material. 



f. Chilling : Embryos are rapidly retarded in -all of their activities by adding to 

 their media some cracked ice. Such embryos may be operated upon and will 

 recover, upon return to normal temperatures, without ill effects. It may take 

 10-15 minutes to adequately stupefy the organisms. 



