EARLY PULSATIONS OF LYMPH HEARTS 385 



Stage 1 (6 d., 12i hrs.) K"'" ^ 3, 4^ J, 



before chloretone '■. ] — • ****^ i »♦■♦♦ 1 



after chloretone 1 :4,000 | , (no. Husc.MovrMENTs: no. lymph ht co.tp.) ! ■ 



alter recovery — «« 1 — ►«h ] ■»«« ***^ — *** ; 



Stage 2 (7 d., 2U hrs.) , , ; | ; 



before chloretone '^ • 1 ■ ^***»* «m»-4»m '■ 



I ! . ' I 1 



after chloretone 1 :4,000 '-» • — ♦-+-« 1 '■ — ,-*-» 1* — h — > i > , 1 — 1 — m — t-^ 



' ' ' ' 1 ' 



after recovery ^ — ' 1 — 1 m I m g 1 > ' 1 1 ►^Ih ; 



Stage 3 (8 d., 16 hrs.) ; , , , ; 



before chloretone ^^ \ Sin — 1-^ — '******** ■ k+«« 1 1 **tr 



after chloretone 1 :4,000 i_, t-n •-• — H **« — ^ 1 t» \ * — m — ♦-•-■ 



after recovery ; hh iiniiiinl ' 1 1 i n' i m 1 ' 1 ' • — | mm i n * — |- 



Stage 4 (8 d., 23 hrs.) [ ^ , , 



before chloretone 1 ,' , t ,' ; , , / , ,—m ' t 1 li 11 t 1 ' — ' \ 



' ' ' ■ I ' ' 



after chloretone 1 :4,000 '.^ ,_n — , 1 1 i m 1 r i n 1 i n 1 — *^ | 



after recovery [ ,,,, ' , , , ' , L_m mm'; > 1 ' > 1 i ; '^ t | 



Stage 5 (13 d., 2 hrs.) . , ; , : , 



•i-u J- 1 1 J. '1 n ' I 1 in; rh n 1 



without chloretone. . . . I, — ►-. U — ■■ — 1— 1 — 1 « , 1 i n 1 1 1 — ^4-m — 1 — > n 1 1 — • 1-| 



1 ■ ; I ! I 



Chart 1 Shows graphically the relation between the lymph heart beats and 

 body movements in different stages, before and after chloretone and after recovery 

 from chloretone. The brackets ^ indicate the duration of the periods of body 

 movement, the spaces between the brackets are the intervals of rest, and the dots 

 are lymph heart pulsations. Selected portions of actual records are reproduced. 

 Spaces between successive beats, length of periods of body movements and of 

 intervals of rest represent actual proportional time intervals. 



six days, in which the lymph heart pulsations, although distinct, 

 are not yet very strong, the lymph heart contracted only once 

 when stimulated directly by puncture with a glass needle. In 

 the older embryos of Stage 1, puncture of the lymph heart caused 

 it to beat six or eight times in succession and these beats were 

 accompanied by tail and body movements. If the chick was 

 anaesthetized at the time of puncture, each beat was accom- 

 panied by a slight mechanical pulling of the tail. 



This early stage of the beating lymph heart, in which the 

 pulsations occur only at the time of the periodic spasms of body 



