HYPOTHERMIA AND BACTERIAL TOXINS 



original containers, and placed into an air incubator generally at 

 35° C for the first 2 hours, then at 31° C for 24 hours. Humidity is 

 kept around 50 per cent, and oxygen administration is continued. 

 After this period, the mice can be kept under normal conditions. 



Normothermic controls are given the same premedication, where- 

 by rectal temperature decreases by 2° C to 5° C, but are immedi- 

 ately transferred to the air incubator, and from that point treated 

 as above. 



Tetanus and staphylococcal toxins and antitoxins were obtained 

 from the Swedish State Bacteriological Laboratory. In preliminary 

 experiments on normal mice of our breed, their MLDj^q neutral- 

 izing doses were determined. The routes of administration of these 

 products will be given for each experiment. 



RESULTS 



In a first experiment presented in Fig. 1, twenty mice were given 

 one MLD^QQ of tetanus toxin subcutaneously. Two hours later hypo- 

 thermia was induced in ten mice which were then kept in this state 

 for about 48 hours. The other ten mice received pretreatment only. 

 Tetanic manifestations were only slight in the hypothermic animals 

 in comparison with those of the controls, but at rewarming, after 

 48 hours, paroxysms grew more frequent and intense. One normo- 

 thermic mouse was lost because it was severely bitten, and two 

 hypothermic ones were lost from drowning. Therefore, recording 

 of survival times could be done only in nine normothermic mice 

 and in eight hypothermic mice, as reported in Fig. 1. 



The average survival within the hypothermic group was sig- 

 nificantly longer than among normothermic controls, as is visible 

 from Fig. 2. In addition, it can be mentioned that two mice only 

 died during the period of hypothermia, two during the first stage 

 of rewarming in the water bath, oneduringthe stay in air incubator 

 at 35° C, and the remaining three 5 or 6 hours after the change of 



137 



