132 



Scientific Proceedings (83). 



to a surprising degree of exactness and the following numerical 

 relations were established : 



1. If a pair of sister leaves (of equal size) are isolated both will 

 produce under equal conditions and in equal time approximately 

 the same mass of shoots, although the number of shoots may 

 differ considerably in the two sets of leaves. 



2. If the mass of one of the two sets of sister leaves is diminished 

 (by cutting out pieces of the leaves), the mass of shoots produced 

 in the two sets is in proportion to the masses of the two sets of 

 leaves. 



3. It had been shown by previous experiments that if a piece 

 of stem is attached to a leaf the growth of the notches of the leaf 

 is retarded. It has been shown by the new experiments that the 

 mass of shoots of leaves attached to a piece of stem is smaller 

 when the mass of the stem is larger and that it also varies directly 

 with the size of the leaf. These quantitative data furnish the 

 basis for a chemical theory of regeneration. 



79 (1257) 



A new method of obtaining samples of the respiratory gases in 

 animals. A demonstration. 



By A. L. Meyer. 



[From the Department of Physiology and Pharmacology, Rockefeller 

 Institute for Medical Research.} 



I wish to demonstrate a new method of obtaining a sample of 

 air from the lungs, bronchi and trachea of the dog. Chloretone, 

 dissolved in olive oil, is given intraperitoneally. The animal is 

 tracheotomized and a T-shaped glass cannula is introduced. A 

 Meltzer pleural cannula (new form) is placed in each pleural 

 cavity. The intrathoracic negative pressure is then restored and 

 the pleural spaces tested for air-tightness. It should be possible 

 to maintain the negative pressure indefinitely. If any change 

 occurs, it must be in the direction of an increase owing to the 

 absorption of gases through the pleura?. 



Both pleural cannulae are now connected with a source of air 



