THE PARS BUCCALIS OF THE HYPOPHYSIS 53 



Obviously, since the aqueous and alcoholic extracts and the 

 colloid were of slight or no nutritive value, additional food 

 substance had to be furnished, but such food substances were 

 only supplied after obtaining a maximum intake of the special 

 glandular substance After turning off the flowing water, the 

 special substance was fed, one half-hour later the nutritional 

 substances, liver and lettuce, being supplied. Twenty-four hours 

 later, after removing all food particles, the process was repeated. 



In the accompanying table (table 3) is shown the number 

 of frog larvae at the commencement of the special feeding and at 

 three subsequent periods. Although the number is relatively 

 small, yet they were average-sized, carefully selected, healthy 

 tadpoles free from injury or malformation. Work with a larger 

 number was precluded, due to the difficulty of securing a suf- 

 ficient amount of the special substances, 90 to 100 bovine hypo- 

 physes being used daily with even this number of specimens. 



substance giving a lipoid-like odor on burning. The extract from five glands was 

 supplied each group of tadpoles (20 to 24) at a feeding. The feeding was done 

 with sufficient rapidity to insure against an extensive solution of the solid substance, 

 and from the rapidly initiated movements of the tadpoles it was certain that they 

 were feeding directly upon this substance. 



The alcoholic extract (Tethelin) was supplied by H. K. Mulford Company. In 

 the feeding of this substance even greater care was exercised than with the aqueous 

 extract, to guard against solution. After a period of a few seconds subsequent to 

 the breaking of the vacuum-sealed tube, the tadpoles would be feeding upon the 

 substance. Fifty milligrams (the extract from five glands) was given each group 

 at feeding. 



In the preparation of the alcoholic residue the method elaborated by Robertson 

 for the extraction of Tethelin was slightly modified. Dehydration was carried out 

 with 95 per cent alcohol instead of anhydrous sodium and calcium sulphates, since 

 the addition of the salts would render the residue useless. Following dehydration, 

 the tissue was thoroughly dried over an electric stove, then extracted in a Bailey- 

 Walker apparatus with boiling absolute alcohol for forty-eight hours. The residue, 

 freed from alcohol, and preserved in tightly corked vials, was supplied in amounts 

 equal to one and a half of the fresh glands at a feeding. 



The colloid was secured from the vestigial cleft, between the glandular and inter- 

 mediate lobes. The amount obtained from the forty-five glands and administered 

 to the twelve to fifteen tadpoles at each feeding varied considerably, but averaged 

 0.5 gram. Occasional very large pieces (0.675 gram) were found, many other 

 glands revealing none. Usually it occurred as a firm, amorphous mass, molded 

 by the shape of the cleft, now and then, however, gels of differing viscosity or even 

 an aqueous-like substance was obtained. Before feeding, the amorphous masses 

 were crushed and mixed with the more fluid portions. 



