JAMES A. MILLER, JR. 247 



of sodium pentobarbital injections in asphyxia is due largely to the 

 depression of metabolism which it produces. 



Tripp's successful use of HoO;. in treating experimental anaerobic peri- 

 tonitis in guinea pigs (180) suggested the possibility of its use as a 

 source of oxygen in asphyxia. Tests showed that 2yk cc/100 gm of 3% 

 peroxide injected intraperitoneally increased survival time, shortened re- 

 covery times for sublethal exposures and was more effective than similarly 

 injected oxygen (1251. Because occasionally animals showed transient 

 symptoms of gas emboli in the brain, 5 cc/100 gm of 1% solutions have 

 been used more recently. These have been effective in prolonging the time 

 of death, shortening recovery time, and in preventing death from exposures 

 lethal for control littermates. Although experiments to test whether hypo- 

 thermia potentiates the protection against asphyxia provided by peroxide 

 are incomplete, the data already at hand indicate that such is the case. 



Adenosine triphosphate is a high energy nucleotide and plays an im- 

 portant role in tissue metabolism. On the other hand it has been shown 

 to be reduced markedly in experimental anoxia (3) and is known to 

 require oxygen for resynthesis. Accordingly, tests were made of the 

 effects of exogenous ATP upon resistance to asphyxia. T.O.D. experi- 

 ments showed only a small increase over controls (21*^^), but this pro- 

 tection was sufficient to permit recovery of 100% of the ATP animals 

 from an exjiosure which was lethal for littermate controls. In the light 

 of these findings we were unprepared for the magnitude of the reduction 

 when sublethal exposures were tried and stages of recovery were timed. 

 Figure 6 shows that the mean times of first breath, attempt to right 

 (RR Attempt), completion of righting (Compl. RRl and crawl were 

 well below that of the controls. The righting reflex is the most consistent 

 of the stages timed. It is entirely spontaneous, and once the animal has 

 gotten upon its feet it will not permit itself to be placed on its side. In 

 these experiments the ATP animals required less than half of the time 

 (46% ± 2.4) of the controls to reach this stage. Comparisons of the activity 

 of ATP, ADP and A]\IP show that the original rationale for its use is 

 untenable. However, data of Green and Stoner (81) on the effects on 

 metabolism of injected ATP and AMP suggest that here too general 

 depression of metabolic requirements may be the mechanism of the bene- 

 ficial effects of the nucleotides (120) . Eff'ects of hypothermia on nucleotide 

 protection against asphyxia are being investigated and metabolic tests 

 will also be made to see if the newborn guinea pig shows the same 

 reaction to injected nucleotides as the adult rat used by Green and Stoner. 



It cannot be predicted a priori whether measures which are individually 

 effective will be additive when they are combined. A beginning has been 

 made in testing the combination of two or more treatments. Table 8 



