^73 



It is true, oasos liaxo I>oon mentioned where ci frog's lleart, which 

 heat no longei' in sheep sernm and oonhl no longer he stimnhited 

 mechanically, was made to contract again by I\ingkk's sohition 

 (Waldkn). Yet the possihihty is not excindcd that in tliese cases the 

 strange sernm lias gra(hially had a poisonons effect. Therefore I 

 shall also leave it an open qnestion if the time dnring which the 

 gut keeps alive wonld not he longer still if, instead of horse-sernm, 

 serum of the same animal, if possible of the same individual, were 

 used. 



The experiments of Ingkrrigtskn with tissue-cnitures in auto-, 

 homo- and hetero-geneons sera have demonstrated the relative 

 superiority of antogeneous sernm to serum of other individnals of 

 the same kind, and of these two sera to heterogeneous ones. Ingk- 

 BRiGTSEN has uot used horse-serum ; this seems to be a particularly 

 indifferent medium. Nnmerous experiments have shown that this 

 sernm is a much better medinm for the gnt than tyrode-solution. 

 The gut of a cavia, for instance, kept in tyrode-solution, was dead 

 after 5 days ; when kept in horse-sernm another piece of the same 

 gnt still moved after 21 days. 



The experiments were carried out in the following manner. 



The animal, a cavia for instance, is killed by decapitation. 



+ 20 cm. behind the slomach a piece of the small intestine, long + 4U cm. 

 is cut out and divided in Tyrode-sokition into 8 pieces long 4 — 6 cm., called 

 a — h. 4 of these {a, b, e, f,) were placed in Tyrode-solution, 4 others {c,d,g,h) 

 in horse-serum. 



Oxygen is led through the 8 glasses. The pieces a, e, c, g, are connected with 

 a writing apparatus to a cymographion (method of Magnus). 



To c and g olive-oil is added. The movements of these 4 pieces having been 

 registered at + 37°, they are slowly cooled down. Then the current of oxygen 

 is stopped. The glasses a, e, and the reserve-experiments ö, f, remain at room- 

 temperature (+ 15°), the glasses c, g and the reserve-experiments d, /? are exposed 

 to a temperature of + 3°. The pieces «Tis, e^j ''Ty^ and gT.^ remain connected 

 with the writing apparatus or are removed with it. 



On the third day after the death of the cavia the pieces a, e, c, and g are 

 connected with the cymographion whilst oxygen is led through, and are slowly 

 heated to 40°. All the pieces move, but not so much as the first time except 

 gSo, the movements of which have become greater. The fluid in all 8 glasses is 

 refreshed after being cooled down and saluraleil with oxyen as on the first day. 

 On the sixth day all are healed etc. ju.st as on Ih.e third day. Piece "Ty^ moves 

 no longer now, not even after the Tyrode solution has been refreshed. The reserve- 

 piece ^^15 does not move either: therefore in Tg rode solution at ± 15° the gut 

 dies before the 4tii day The three other pieces el\, ''Sy,, and nSg, still move, 

 the first two less again than last time. On the ütii day everything is heated again 

 etc. Piece eT-^ moves no longer, not even after the Tyrode-solution has been 

 refreshed. Nor does the reserve-piece ./ T3 move: hence in Tyrode-solution at ± 8° 



