CULTURING OF AMPHIBIAN EMBRYOS 



k9 



ORIGINAL FBOG BINGEB'S: (S. 



NaCl 

 KCl . 

 CaClg 



Ringer I88O: Jour. Physiol. IJOSo) 



0.65 grama 



O.OII+ 



0.012 



0,02 



NaHCOj .... 

 Na%PQl+,, 

 Glucose 

 Water 



0.001 

 0.20 

 to 100. 



SPRING WATER : 



Great Bear Spring Water. This has proven to te entirely satisfactory for the early 

 development of Anuran embryos particularly. (Available in N. Y. City) 



URODELE STOCK SOLUTION : 



The same constituent salts are found in the Urodele media hut in slightly different 

 proportions. This stock solution could be made up in 20 liter carboys and could be 

 diluted for either operating or growing media, using the Great Bear Spring Water for dilu- 

 tions. 



NaCl 70.0 grama 



KCl 1.0 " 



CaClg 2.0 



Spring Water 10.0 liters 



URODELE OPERATING MEDIUM : 



This medium la slightly hypertonic to the grovlng medium. Embryos may be left in 

 this medium for several hours after transplantations, etc., and then should be transferred 

 to the Growing Solution. 



Urodele Stock Solution 2 parts 

 Great Bear Spring Water 1 part 



URODELE GROWING SOLUTION : Urodele larvae grow very satisfactorily in this medium. 



Urodele Stock Solution 1 part 



Great Bear Spring Water h parts 



In making up aynthetic media it is recommended that glass distilled water be used 

 where it is practicable. It has been found that with copper stills, enough copper goes 

 into solution, in some atills, to make the water slightly toxic to embryos. In any 

 crucial experiment the Investigator should pre-test the medium against the embryos to be 

 studied to that he can eliminate this as a possible factor in his experimental results. 

 The data from the Osmo- Regulation experiments will be of value in this regard. 



FOOD 



FOR TEE LARVAE: 



Feeding is not necessary for some days after the mouth of the tadpole (larva) is 

 open. This is because all amphibian larvae are provided with an abundance of reserve 

 food in the form of yolk which is digested and absorbed directly by the tissues. 



Anura : 



Feeding is not necessary until stage #25. Most Anuran lai-vae are vegetarians, 

 and the most satisfactory food consists of slightly boiled lettuce or spinach. These 

 greens should be thoroughly washed to rid them of any adherent arsenic or lead which 

 may have been sprayed on them as Insecticides by the gardener. Boiling the greens 

 simply softens the plant tissues. The danger, at least in the beginning, comes from 

 over-feeding. The tanks must be cleaned daily to keep faecal and bacterial accumula- 



