208 



Scientific Proceedings (108). 



material, that an homogeneous, intercellular, gelatinous material, 

 permeates various regions of the embryo. This substance as 

 seen in a living embryo is perfectly transparent and is, therefore, 

 difficult to detect under the binocular or under a compound 

 microscope equipped for ordinary illumination. It can, however, 

 be readily studied with a microscope equipped for dark field 

 illumination and numerous observations on this material have 

 been made in this manner. 



The present observations on the ground substance in living 

 amphibian embryos, therefore, confirm those previously obtained 

 with prepared material and show conclusively that the primary 

 substance in connective tissue formation is a secreted, inter- 

 cellular material. 



113 (1573) 



Effects of pilocarpine upon salivary fistula dogs before and after 



coli injection. 



By H. G. Barbour and B. P. Freedman. 



[From the Department of Pharmacology, Yale University School of 



Medicine.] 



In each of two healthy dogs was made a fistula of Wharton's 

 duct. After several weeks a standard dose of 0.5 mgm. per kilo 

 pilocarpine hydrochloride was injected at intervals of two or 

 three days. After each dose the curve of secretion was followed 

 for two hours by weighing the saliva on cotton pledgets by five 

 minute periods. 



Contrary to expectation, a normal curve was not readily 

 established. The secretion increased with each experiment until 

 both the total for two hours and the figure for the maximum indi- 

 vidual five-muinte period were approximately doubled in one 

 case and trebled in the other. After six to eight injections the 

 results became more constant. This gradually increasing sensi- 

 tivity to pilocarpine has not yet been explained. 



After a fairly constant degree of sensitivity to the drug had 

 been established each of the above animals received an injection 

 of ]/2 c.c. per kilo of a coli vaccine (one million million killed coli 



