202 ECOLOGY AND LIFE HISTORY OF THE COMMON FROG 



knowledge there that can be of much scientific importance. For 

 example, I know that some work on newts by a most competent 

 scientist was held up for a time because the technique of keeping the 

 animals in health was incredibly faulty. The late L. A. Lantz, who 

 had great skill in keeping these animals, supplied the information. 

 Then again, important medical work on schistosomiasis was delayed 

 because the snails which are the vector of the disease did not live well 

 in laboratory vessels. The problem was solved by the application of 

 the technique of the balanced aquarium, with a mud slope at one end. 

 Tliis was a device that anyone with a pet-keeper's knowledge would 

 have applied from the beginning. 



If animals show signs that they are Uving normal lives in captivity, 

 such as by coming into breeding condition spontaneously year after 

 year, I think that observations on them can be quite relevant to what 

 happens in the field. It is therefore well worth while studying what 

 pet-keepers do, and if possible persuading them to write accounts of 

 their technique. 



REFERENCES 



Andrew ARTHA, H. G. and Birch, L. (1954) The Distribution and Abundance of 



Animals (University of Chicago Press). 

 Brownlee, K. a. (1949) Industrial Experimentation (H.M. Stationery Office, 



London). 

 Davidson, J. and Andrewartha, M. G. (1948) J. Anim. Ecol. 17, 2, 200-22. 

 Davies, O. L. (1949) Statistical Methods in Research and Production (Oliver & 



Boyd, London). 

 Elton, C. S. (1927) Animal Ecology (London), 

 EzEKiEL, M. (1930) Methods of Correlation Analysis (Wiley, New York. Later 



editions). 

 Fisher, R. A. (1932) Statistical Methods for Research Workers (Oliver & Boyd, 



London. Later editions). 

 GuNN, D. L. and Symmons, P. M. (1959) Nature, Lond., 184, No. 4696, 1425. 

 Kendall, M. G. (1952) The Advanced Theory of Statistics (GrifFen, London). 

 MoRAN, P. A. P. (1953) Aust.f. ZooL, I, No. 1,163. 

 Savage, R. M. (1935) Proc. zool. Soc. Lond., i, 49-98. 

 TiNBERGEN, N. (1953) Social Bcliaviour in Animals (Methuen, London). 

 TiPPETT, L. H. C. (1952) The Methods of Statistics {WH^^ms 8c Norgate, London). 

 Williams, C. B. (1951) Trans. IXth Int. Congr. Entomol. i, 174-89. 



