MITOCHONDRIA IN NERVE CELLS 47 



Next we may mention the relation of mitochondria in nerve 

 cells to the transition of a mammal from the warm-blooded 

 (homoiothermal) type with a body temperature of about 36°C. to 

 what is in many respects the cold-blooded (poikilothermal) type 

 with a temperature only slightly higher than that of the surround- 

 ings, and which reached as low as 7°C. in one animal here 

 involved. This striking alteration seems to have had no effect. 



Finally, attention is drawn to the fact that during dormancy 

 and for as long as three weeks after waking up, i.e., until the 

 last animal was killed, no food or water was available. This ina- 

 nition during hibernation as well as after becoming active did 

 not apparently affect the mitochondria of nerve cells, although 

 during the three months of winter-sleep the body weight decreases 

 about one-fourth while the animals allowed to live several weeks 

 after waking up lost fully one- third. 



SUMMARY 



1. Profound dormancy such as is seen in a fully hibernating 

 marmot with a rectal temperature as low as 7°C. does not affect 

 noticeably in any way the mitochondria of the central nervous 

 system or of the spinal ganglion. 



2. Complete inanition for three months during winter-sleep 

 and for three weeks after waking up does not modify the mor- 

 phology, number, or distribution of mitochondria in nerve cells. 



3. Perfusion with oxygenated Locke's solution at body tem- 

 perature for a period as long as one hour does not modify the 

 mitochondrial content of nerve cells beyond what is produced by 

 a more rapid flushing out of the vessels for a duration of only 

 fifteen minutes. 



