The Nutrition of Hydra 



David L. Claybrook 



Dcpt. of Phijsiolo^ij 6- Fliarmacologij , Wayne State Universitij College of Medi- 

 cine, Detroit, Michigan. 



The study of hydra nutrition is in its infancy. In fact, we are 

 not aware of any investigation of specific nutrient requirements 

 prior to our own. I suspect that the absence of such studies has been 

 due to the complexity of the prol^lem rather than to a lack of 

 appreciation for its importance. The laboratory culture of hydra 

 was more of an art than a science until Dr. Loomis' fundamental 

 research defining environmental conditions for optimal growth 

 ( 12 ) . The numlier of environmental variables was then greatly 

 reduced to the point that the rate of growth coidd be directly con- 

 trolled by limiting the food supply. 



The hydra's apparent refusal to ingest non-living food made it 

 essentially impossible to feed a formulated diet. When the gluta- 

 thione control of the feeding reaction was revealed (3), it offered 

 a means for feeding to the animals particulate preparations of the 

 experimenter's choice. With these possibilities in mind, we began 

 a study of hydra nutrition. 



We undertook this investigation for two main reasons. First, 

 we wanted to know to what extent the hydra's requirements were 

 similar to and different from those of other animals. With the 

 exceptions of the protozoa and insects, very little work has been 

 devoted to the nutrition of invertebrates. Information on coelen- 

 terate nutrition would contribute significantly to our knowledge of 

 comparative biochemistry. 



The second, and primary purpose of the project was to in- 

 crease the usefulness of the hydra as a biological material for the 



iln part from a dissertation submitted to the Graduate School, The University of 

 Texas, in partial fulfillment of the requirements for the degree of Doctor of Phi- 

 losophy, August, 1960. 



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