Reprinted from the PSOC3EDINGS OF THZ SooI1TT FOn EXPE&IMUNTAL BiOLOGY
A"D XBDION, 
1927, xxv. pp. 218 219 
3779 
Biometric Studies Upon Development and Growth in Amblystoma 
Punctatum and Tigrinum. 
E. M. PATCH. (Introduced by J. 8. Nicholas.) 
Fron the Osborn Zoological Laboratory, Yale University. 
Measurements of Amblystoma punctatum and tigrinum have been 
made in order to secure data upon the normal rate of growth and 
upon the modifications of this growth rate by experimental pro- 
cedure. Data show that the rate of enlargement during embryonic 
stages is dependent upon the temperature, the size at any named 
stage being correlated with the size of the egg. Length increase in 
the embryo is made at the expense of the other dimensions. The 
curve of absolute increments of length when plotted against time 
during embryonic development is S-shaped, terminating at the end 
of this period. 
The mean lengths of Amblystoma punctatum, tigrinum, and Axo- 
lotis at this point of development are 15.61 mm., 14.07 mm., and 
11.96 mm., respectively. Tables for mean length, standard devia- 
tion coefficient of variation, and the probable errors of these quanti- 
ties demonstrate the value of the criterion used. 
Growth following the embryonic period is dependent upon food- 
quality, quantity, and frequency of feeding. Where feeding is alike, 
size relations of the embryonic period hold for larval growth. No 
food has been found as adaptable for early use as the natural diet 
which consists of small aquatic forms. Beef-liver can be used at 
early stages and produces a remarkable acceleration of growth. 
Of the tissues tried, kidney is second in value. 
In the later larval development and adult life, beef muscle produces 
greater growth than liver; at these stages, liver feeding is attended 
by excessive glandular production, by lack of growth, and often with 
loss of appetite. Death sometimes follows. There is a weakening 
of normal peristaltic action, which can be compensated for, partly at