536 



APPENDIX. 



till the swollen glue melts. Add to this about an equal volume of tlie saturated Berlin 

 blue (§ 1449; solution heated to about 80 or 90 Centigrade. Mix thoroughly, and if any 

 dirt is present, filter through fine flannel. The solution may be thinned with water. It 

 must of course be warmed when it is used, and the animal into which it is to be injected 

 should be warmed to at least 30° C. The material soon becomes moldy in warm weather, 

 so only about the amount needed should be made at a given time. 



Injections with colored glue are made precisely as directed in § 359. After the injec- 

 tion is finished, allow cold water to flow upon the animal or set it away in a cool place. 



§ 1451 (§§ 1085, 1091). Obtaining Frogs and Menobranchi.— Notwithstanding the 

 abundance of frogs in certain localities, they are not always obtainable when wanted for 

 anatomical and physiological purposes, and laboratories should keep a supply on hand. 



Boys sometimes capture them, but are apt to injure them. Large frogs may some- 

 times be had from restaurants or from large dealers in fish luce E. G. Blackford, of Fultou 

 Market, New York city. Frogs abound in the marshes near Montezuma, N. T, and may 

 be had at a moderate price from Mr. Fennimore Helmer of that place. 



Frogs may be transported long distances in a box of wet grass if a few airholes are 

 made. They should be kept in a spring, or in a dark conered tank or vessel through which 

 water flows, or in which it is frequently changed. The cover is needed both to prevent 

 their escape and to retard their vital changes. In spite of care, few survive more than 

 three months ; the larger ones often die within as many weeks. 



§ 1453. Mendbrandii abound in the lakes of central New York, but are not easily taken 

 with the net on account of the depth of the water, and the supply from that source is 



therefore variable. We have usually been 

 able to obtain them in considerable num- 

 bers at short notice from Mr. Russel Dee, 

 of Harmar, Ohio. Menobranchi cannot 

 live long out of water, and the water should 

 be changed often. For transportation, not 

 more than three should be put in a pail of 

 water, and they should be shipped very 

 promptly. They may be kept easily in 

 aquaria, especially if a shelter is provided 

 under which tbey can screen themselves 

 from the light. 



Alcoholic examples of the above named 

 animals, as well as of many other forms, 

 domestic and foreign, may be had from 

 the Natural History Establishment of Prof. 

 H. A. Ward, at Rochester, N. Y. 



§ 1453 (§ 1086). Pithing Frogs.— 

 This is an expeditious and approximately 

 painless way of killing frogs for anatomical 

 and experimental purposes. The frog is to 

 be grasped as shown in Fig, 130— the pol- 

 lex upon the middle of the back, the me- 

 dius, annularis and minimus across the 

 belly so that their tips are related to the 

 right arm and leg as represented, and the index upon the head. In this way the most 

 active and powerful frog may be held securely, but the grasp may be aided by a bit of 



Fig. 



180. — Method op Holding a Frog 

 FOB Pithing. 



