INTRODUCTION 



The success of any Symposium usually hinges on the participation 

 of a few key individuals. One such person, in my judgment, whose 

 early commitment as a participant undoubtedly influenced the accept- 

 ance of others, is Dr. Dan Campbell, He will lead the session this 

 afternoon on the influence of cold on the immune response. Rather 

 than give the impression of attempting to anticipate his remarks 

 (which I would never presume to do), I am going to comment only 

 briefly on this topic, Immunologists have refined their techniques 

 to such a degree that they are the envy of many research biologists. 

 Indeed, their methods have been applied wherever possible to prob- 

 lems fundamentally alien to those classically within the scope of 

 their specialty. Immunology is quantitative biology at its best, and 

 may possibly be considered the parent of molecular biology. To de- 

 termine with a high degree of precision the level of response to 

 antigenic stimulation does not necessarily make evident, however, 

 the reason why one group of animals reacts differently from another. 

 We can expect to learn more about these phenomena from Drs. I, L, 

 Trapani and William Northey, who have been concentrating in this 

 area of work for some years. It is a great pleasure to welcome not 

 only them, but also one of two members of the group who make this 

 Symposium international. Dr. Gosta Tunevall will speakfirst on the 

 effects of hypothermia on the response of mice to bacterial toxins. 

 This is one of four papers (two from Dr. Tunevall) dealing specifi- 

 cally with animals at reduced body temperature as it influences 

 host- parasite interaction. The first is concerned with the important 

 problem of how hypothermia alters the physiological or pharma- 

 cological properties of a soluble toxin. These bacterial products 

 must exert their primary action at the enzymic level. If hypothermia 

 reduces metabolic rate, as it must since the velocity of all chemical 

 reactions is lowered by a drop in temperature, then there should 

 be a less acute action of toxin in animals at reduced body tempera- 

 ture. As logical as this may seem, there are also other alternative 

 effects that would make this untrue. Hypothermia, as it becomes 

 more and more severe, affects different organs such that their 

 activities do not change in parallel (Adolph, 1959), Physiological dis- 

 tortion occurs, compared to the integrated normal state, such that 

 some functions cease at a temperature where others continue. 

 Breathing may stop at about 15° C, but the animal can survive and 

 recover if artificial respiration is administered. Cessation of heart 

 beat then becomes a cause of death in animals so maintained and 



