ACTION OF ERGOT 361 



note any change in the appearance of the comb and wattles ? 

 If so at what time after the injection is the change at its 

 maximum? If you had a standardized preparation and a 

 non-standardized preparation of the fluid extract of ergot 

 could you compare the relative strengths of these two solu- 

 tions by their relative actions in the same sized doses on 

 roosters of approximately the same size, age, and sensitiv- 

 ity to the drug ? This is one of the methods sometimes used 

 to standardize ergot. (For literature, see Edmunds and 

 Hale : Bulletin No. 76, Hygiene Laboratory, U. S. Public 

 Health and Marine Hospital Service; also Pittenger: Bio- 

 chemic Drug Assay Methods, P. Blakiston's Son & Co.) 



EXPERIMENT C. 

 Ergot. (Frog: Capillary Circulation.) 



1. Take a thin board about four inches wide by seven or 

 eight long (a cigar box lid is very satisfactory) and cut a 

 hole about one inch in diameter in one end and near the side 

 as shown in Pig. 305. Fasten a frog, ventral side down- 

 ward, on the board as indicated with strings (except the 

 right hind leg). Draw the web of the right hind leg over 

 the hole in the board and fasten (with twine strings) the 

 toes in an extended position to spread the web out well. 

 Place the board on the stage of a microscope and examine 

 the capillary circulation in the web. Note carefully the size 

 and appearance of the capillaries and the rate of flow of 

 the corpuscles. Make a sketch to show what you see, ob- 

 serving especially the size of some of the vessels which you 

 see where they bear a certain relation to the pigment spots. 

 If the diameter of the arteriole changes can you detect the 

 variation by reference to the pigment spots ? 



Under the skin of the back inject one-half cubic centi- 

 meter of fluid extract of ergot and watch the circulation 

 carefully from time to time as the drug is absorbed. Do 

 you get any change in caliber? If so how do you explain 



