Obstructed Respiration. 



73 



Levulose was added to urine and subsequently quantitatively 

 recovered after treatment of the urine with lead acetate to remove 

 coloring matter and inorganic salts. 



43 ("07) 



A method for obtaining suspensions of living cells from the fixed 

 tissues, and for the plating out of individual cells. 



By Peyton Rous and F. S. Jones. 



[From the laboratories of The Rockefeller Institute for Medical 



Research.] 



The method depends on the ability of living tissue cells to 

 withstand tryptic digestion. It is applicable to such cells as will 

 proliferate in vitro. Bits of tissue are cultivated in plasma, ac- 

 cording to Burrows's modification of Harrison's technic, and when 

 growth is well under way the preparation is flooded with trypsin 

 dissolved in Locke's solution. Under the influence of this fluid 

 the growing cells contract into spheres, and with the digestion of 

 the fibrin network they are liberated. Suspensions of indi- 

 vidual cells are thus obtained comparable to suspensions of leuko- 

 cytes. When washed and plated anew in plasma the cells put 

 forth processes and proliferate. The digestion and plating can 

 be repeated. The method is most successful with tissues that 

 grow loosely in strands or a network, — sarcoma, choroid, endo- 

 thelium (?), connective tissue, — in distinction from those prolifer- 

 ating in sheets, as do the epithelial tissues. The cells of these 

 latter are usually liberated in clumps, not as individuals. 



44 ("o8) 



The carbon dioxide content of blood and alveolar air in obstructed 



expiration. 



By E. D. Friedman and H. C. Jackson. 



[From the Laboratory of Physiology of University and Bellevue 

 Hospital Medical College.] 



In the course of a study of the effects of respiration on the cir- 

 culation and more especially the modification of these effects in 



