Abstract
The experimental results of the present paper and the knowledge gained by former inhalation experiments reveal that only those experimental procedures are suitable that make animals inhale high concentrations of smoke during a long period of time. The present results let appear how inhalation experiments are most favourably arranged. It has to be guaranteed that the animals are not endangered and that considerable quantities of smoke are inhaled. The distance between cigarette and animal should be as small as possible. Intervallic smoking seems to be advisable. The well-developed filtration capacity of the upper respiratory tract of animals usually breathing through their nose does not exclude the possibility of making fruitful inhalation experiments with rodents. The value of such experiments does decisively depend on the animal species