1 84 



Charles R. Stockard 



Eggs that remained as long as thirty hours in ^ m distilled water 

 solutions of KCl would recover if placed in sea-water. Other 

 eggs were left for three days in KCl f m distilled water solutions, 

 and afterward recovered, the heart beginning to beat, etc., when 

 returned to sea-water. Normal embryos several days old were 

 very readily killed if subjected to even weak solutions of KCl; 

 their heart's action being stopped. It thus seems as though an 

 embryo may live and develop without its heart ever having con- 

 tracted, but if it had once begun to contract any cause that may 

 stop this contraction proves fatal. My results then in a general 

 way agree with Loeb's observations though I should take exception 

 to his statement that the circulatory system develops normally 



even though the blood does not circu- 

 late. The major parts of the system do 

 seem to develop but by no means nor- 

 mally, the heart being small and weak 

 and it is often only a straight tube with 

 the balloon-hke pericardium surround- 

 ing it. Many clots of red corpuscles 

 are noted in several of the sinuses. 

 The above facts are also of interest in 

 connection with Howell's analysis of 

 the inhibitory action of the vagus nerve 

 on the heart beat as being due to the 

 liberation of K-ions about the nerve 

 endings. 



A mixture of a ^ m KCl and a molecular NaCl solution was 

 prepared with 60 cc. of the former to 10 cc. of the latter. This 

 mixture showed the same general effect on the eggs as the simple 

 KCl solution; the blastoderm bulged up slightly and the yolks 

 were shrunken. Many embryos, however, seemed stronger and 

 better developed with more pigmentation and with larger red 

 blood clots. Some of these embryos were placed in sea-water 

 when seven days old but failed to recover.. 



A CaClj i m solution in distilled water proved highly toxic. 

 The blastoderms flattened down, the cells apparently spreading 

 unusually far apart. The eggs died within about twenty-four 



Fig. 12 An embryo from a mixed 

 solution of MgCl2 i m + NaCl \ m 

 when forty-three hours old, showing 

 twollen, pc, pericardium. 



