152 



Scientific Proceedings (39). 



Without going into a detailed discussion of these structural 

 alterations, I may say that these findings support my former view, 

 namely, that nutritional disturbances in such vascular tissues are 

 of fundamental importance in interpreting the results. 1 And fur- 

 thermore, with our present knowledge such observations do not 

 help to explain the nature of pathological processes such as arterio- 

 sclerosis, which result in structural alterations in blood vessels. 



96 (506) 



Modification of tissue oxidations in vitro. 



By F. V. GUTHRIE. (By invitation.) 



[From the Department of Physiology and Pharmacology of the 

 University of Pittsburg.] 



The purpose of this investigation was to determine the in- 

 fluence of certain substances upon oxidations by tissues in vitro, 

 with a view of casting some light on the relation between such 

 substances and tissue respiration after the administration of these 

 substances to animals. The general method of investigation was 

 similar to that practiced by Yeo. 2 Tissues and solutions of oxy- 

 hemoglobin of amphibians, reptiles, birds and mammals were em- 

 ployed. The tissues were placed in freshly prepared oxyhemo- 

 globin solution made from fresh blood obtained from the same 

 animal. The mixtures were made in test-tubes and for the most 

 part air was not entirely excluded. The darkening of the hemo- 

 globin solution as observed directly and the appearance of reduced 

 hemoglobin as shown spectroscopically were taken as indicating 

 the amount of reduction. 



Preliminary experiments with mammalian tissues gave a value 

 for different tissues somewhat different from that obtained by 

 Bert, 3 who employed a different method. Also the results showed 

 that tissues of warm blooded animals reduce such oxyhemoglobin 

 solutions more actively than those of cold blooded animals; this 

 observation agrees with the results of Battelli and Stern. 4 For the 



1 Jour. of the Amer. Med. Assoc., 1908, 1, 1035. 

 2 J our. of Physiol., 1885, vi, 93. 



3 Legons sur la physiologie comparee de la respiration, Paris, 1870, p. 46. 

 4 Jour. de physiol. et de path, gen., 1907, ix, 1. 



