EFFECT OF IODINE ON LARV.E OF SALAMANDERS. 317 



be borne in mind that the ineffectiveness of inorganic iodine in 

 limb development of salamanders is merely due to the above- 

 mentioned peculiarity of the thyroid apparatus of the salamander 

 larvae and not to the fact that limb development in salamanders is 

 independent of the thyroid hormone and of metamorphosis. In- 

 organic iodine could not accelerate limb development of salaman- 

 ders, even if iodothyrine would have an accelerating effect. 



SUMMARY. 



1. Tadpoles of Rana sylvatica were kept in iodothyrine and in 

 solutions of inorganic iodine. Both substances were found to 

 accelerate limb development. This result confirms the observa- 

 tions of previous investigations. 



2. Embryos as well as larvae, in early stages, of Ambystoma 

 maculatmn were kept in iodothyrine and in inorganic iodine. 

 Neither of these substances accelerated the development of the 

 limbs, although iodothyrine caused rapid metamorphosis of the 



salamander larvae. 



REFERENCES. 



1. Uhlenhuth, E. 



'19 J. Gen. Physiol., i, 525. 



2. Uhlenhuth, E. 



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3. Gudernatsch, J. F. 



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4. Swingle, W. W. 



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5. Uhlenhuth, E. 



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6. Emerson, E. T. 



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'19 J. Exper. Zool., xxvii, 417. 



