1912] 



William J. Gies 



6i 



through rubber into various solid and liquid media, among them 

 both solid fat and oil. Thus, when Sudan III is dissolved in melted 

 lard, the red liquid poured into a rubber bag, the bag supported in 

 melted lard in a bottle, and the apparatus promptly immersed in ice 

 water — the fatty matter will congeal before any sign of pigmentary 

 diffusion occurs but, in a few hours, a reddish tinge will develop 

 outside of the bag, and on each successive day for several weeks 

 further extension of the pigmented matter may be witnes'sed, until 

 the whole of the external lard is deeply suffused with red. This 

 process takes place quite rapidly when the lard and apparatus are 

 kept in a thermostat at 40° C. 



The demonstrations were intended to exhibit a few instances of 

 such pigmentary diffusions as occur speedily enough at room tem- 



perature to yield positive results within an hour. The accompany- 

 ing summary indicates briefly the precise nature and results of the 

 demonstrations (including two control tests — 4 and 5), which were 

 made with thin rubber bags in ordinary glass bottles. 



The bags were securely supported in the bottles, and the mix- 

 tures were shaken occasionally during the demonstration. The 

 bags were found, after the adjournment of the meeting, to be with- 

 out defects. 



V. COMPARATIVE DIALYSIS EXPERIMENTS, WITH 

 DEMONSTRATIONS" 



When dry bags of rubber, gold-beater's skin, parchment, and 



collodion, each containing olive oil and Sudan III, are separately 



" Goodridge and Gies : Proceedings of the Society for Experimental Biology 

 and Mediane, 191 1, viii, p. 74. 



