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THE BIOLOGY OF HYDRA : 1961 



prepared in our laboratory with reports in the hterature describing 

 the activity of other Physalia toxin preparations. Earher investiga- 

 tors, ahnost uniformly, have homogenized and extracted entire 

 tentacle material. It will later appear that there are active extra- 

 nematocyst substances present in the tentacle; however, the bio- 

 chemistry and pharmacology of these materials has not been 

 studied in our laboratory. 



Isolated nematocysts may be concentrated by settling and de- 

 cantation of the supernatant water. They do not survive centri- 

 fugation without discharge so it is necessary to permit them to 

 settle by gravity alone. The putty-like concentrate resulting from 

 our procedure is virtually free of tissue fragments and contains 

 very few (less than 1%) discharged nematocysts. The concen- 

 trated nematocysts are frozen and stored in the deepfreeze where 

 they retain their reactivity for periods of at least four years. 



Surviving nematocysts are homogenized in an all-glass homog- 

 enizer in a minimum volume of distilled water for about twenty 

 minutes, or until an aliquot shows no more than 10% unbroken 

 capsules. The resulting brei is centrifuged at 4° in a refrigerated 

 centrifuge at 15,000 > gravity; the residue is resuspended in a 



TABLE 1 

 Amino acids in an acid hydrolysate of the crude toxin 



