118 WALTER NEUHAUS 



walled 40 mm diameter rubber tube was held quite loosely around the 

 animal. This respiration belt was connected to a Marey's capsule via a 

 narrow bore rubber tube. The pen of the capsule recorded the pressure 

 changes on a Kymograph. In order to avoid all nonrelevant stimuli, the 

 experiments were performed in a darkened silent room. The little light 

 needed for manipulation (a low-voltage lamp) was so situated that the 

 animal could not perceive anything of the handling of the apparatus. The 

 animal was in direct light, while all the manipulation took place in dim 

 light screened from the animal. 



HoO 



2"-'n 



./^.A-^/' 



Fig. 8. Record of the respiration of goose No. 1. Water and ethyl mercaptan. 



The recording system was filled with air and a period of calm, regular 

 respiration was waited for. Then a vessel containing a concentrated 

 odorous substance was quietly opened under the beak of the bird, and 

 held there 20 to 40 sec. The animal could not see the manipulation or the 

 vessel. As controls water vessels were introduced before, after, and be- 

 tween the odour-containing vessels. After each olfactory test the room 

 was ventilated for 10 min to abolish any traces of the odorous substances. 

 Figures 7-16 shows some recordings from two ganders and one goose. 

 The regular respiration, i.e. a fairly fast inspiration, followed by an at first 

 fast and later slow expiration — is usually changed by the introduction of 

 the olfactory stimulus to a more irregular pattern. Frequently, the -first 

 inspiration shortened after the introduction of the stimulus and the second 

 lengthened, or the respiratory pattern changed to a series of short puffs. 

 The controls with water showed no such changes. The first pictures show 



