244 THE BIOLOGY OF HYDRA : 1961 



LOOMIS: I have often tried to get micro-pipettes into the mouths 

 of H. littoralis and out again without having them then regurgitate 

 what I put in their stomachs. Perhaps you open their mouths 

 with gkitathione? 



CLAYBROOK: No, I force it open. 



LOOMIS : Maybe that's the secret! 



CLAYBROOK: Yes. Then I wait until he closes his mouth on 

 the pipette before injecting the material. 



LOOMIS : And then it is water-tight as you pull out? 



CLAYBROOK: The semi-solid consistency of the medium is es- 

 sential here. You can't use a liquid. 



LOOMIS : How much agar do you use? 



CLAYBROOK: I use 0A%, which is relatively thick. The Hydra 

 closes its mouth when the pipette is withdrawn and the viscous 

 solution remains in the gut. 



LOOMIS : Will it flow down a microcapillary? 



CLAYBROOK : Yes, if under pressure. 



