362 THE POPULAR SCIENCE MONTHLY 



tion (i. e., interchange of gases in the lnngs) there is, when the thoracic 

 muscles and diaphragm are not acting (i. e., complete cessation of move- 

 ment) is maintained principally by the " cardio-pneumatic " move- 

 ment. 10 A hibernating dormouse may not give a single respiration for 

 ten minutes, then takes from ten to fifteen breaths, at the end of which 

 it again lapses into a state of quiescence for a period of several minutes, 

 when the spasmodic respiratory act again occurs. The same animal, 

 when in a normal waking state, breathes at the rate of eighty or more 

 respirations a minute. Similar results are obtained in other animals. 

 It has been observed that hibernating bats and marmots could be kept 

 for hours in an atmosphere of carbon dioxide gas, without suffering any 

 ill effects, whereas a bird or rat placed in the same chamber died almost 

 at once, thus showing that in the hibernating state the consumption of 

 oxygen is extremely small or in other words very little oxygen is re- 

 quired by the hibernating animal (owing to the quiescence and lowered 

 metabolism of the animal and naturally for the same reasons very little 

 carbon dioxide is given off). Saissy has observed that the amount of 

 oxygen taken in by a dormouse varied according to the activity of the 

 animal, and so in true hibernation the amount of the intake of oxygen 

 is naturally very small. 



Circulation 



During hibernation, the force and frequency of the heart-beat is 

 greatly reduced. In the case of the bat and dormouse, it is as low as 

 fourteen or sixteen per minute, while in these animals in the active 

 state it is one hundred and over. Hill and Pembry by applying a 

 stethescope to the chest of a hibernating bat, make the observation that 

 no sound of the heart-beat could be heard, I can confirm this observa- 

 tion as applying to the hibernating ground-hog in British Columbia, 

 also, whereas with the animal awake and active, the sounds were so 

 loud that they could be heard distinctly when the ear was an inch away 

 from the animal. 



I have found, and can confirm other observers, that the blood during 

 hibernation has an arterial hue (bright red) in the veins, and, on the 

 other hand, Marshall Hall states that it has a venous color in the ar- 

 teries. 



Digestion 



The activities of the digestive organs vary according to the habits 

 of the different animals. Some, much as the dormouse, marmot ( ?) 

 and hamster, store up food in the autumn which they consume during 

 the winter in their waking intervals. Naturally, then, their digestive 



10 Cardio-pneumatic movement. Here the visible movements of respiration, 

 dilation and contraction of the thorax, have ceased, but still air (a very small 

 amount) is drawn into and expelled from the lungs. This is due to the heart's 

 action, it also being contained in the thoracic cavity, hence its contraction and 

 dilation so alters the pressure in the thorax that an interchange of respiratory 

 gases is produced in the lungs. 



