IOO VERA DANCHAKOFF AND S. M. SEIDLIN. 



lar digestive tract, no other results would be obtained, than those 

 described by the authors in relation to the stroma cells of the 

 tadpole. Paraffin would produce no direct effect upon the lin- 

 ing of the digestive tube, some of the granules of India ink 

 might be incorporated by cells, if a sufficiently long contact could 

 have been secured. Croton oil would produce an intensive in- 

 lammation, aseptic if applied by itself in a milieu free of bacteria. 

 Starch granules would be digested, but even these only in certain 

 parts of the digestive tract. 



Our experiments consist of introducing various amounts of sus- 

 pensions of different protein substances into the thin edges of the 

 tadpole tail. The injections were made with extremely fine glass 

 pipettes. After numerous more or less unsuccessful attempts to use 

 rather complex and apparently well-devised methods of injecting, 

 recourse was taken to the simple and efficacious way used by Doctor 

 Clark and courteously demonstrated by him. The substances, 

 suspended in saline solution, were blown into the tissue by lung 

 pressure. The injections were made both into the dorsal and ven- 

 tral edges of the tail. The epidermis of the tail is easily pierced 

 in the caudal part of its edge by the fine end of a glass pipette con- 

 taining a thick suspension of a fine pulverized protein, between 

 its dorsal border and the axial strand of the denser tissue. The 

 pipette is then pushed at about equal distance from dorsal and 

 ventral borders of the transparent plate for about 2-4 mm. in the 

 cranial direction. The other end of the pipette is connected with 

 a rubber tube. The substance is introduced into the tissue of the 

 tadpole by blowing into the tube, considerable effort being re- 

 quired in order to force the substance through the glass capillary. 

 It is essential, while blowing, to gradually withdraw the glass 

 pipette from under the skin. 



Since large amounts, as well as a few particles of various 

 substances were introduced, medium and large-sized tadpoles 

 were chosen for the experiment. A successful injection could 

 be easily determined, the material injected appearing under the 

 skin as an opaque streak. Though in some cases the substances 

 were introduced in excessive amounts (the strand of injected 

 substance appearing to be over 3 mm. in length and to occupy half 



