The first experimental study of sleep deprivation. Manaseina "performed her experimental investigation on 10 puppies (2, 3, or 4 months old), fed by their mothers, by keeping the animals in constant activity. The experiment came to the straightforward conclusion that "the total absence of sleep is more fatal for the animals than the total absence of food", since the dogs could be rescued after 20-25 days of starvation, but they were "irreparably lost" after a sleep deprivation of 96-120 hours. De Manaceine also noted that older dogs were more resistant to insomnia than younger ones and that body temperature decreased from the second day of sleep deprivation on and was 4,5, or even 5.8°C lower than normal before the animal's death. After the initial decrease of body temperature (0.5-0.9°C), locomotor activity had started becoming "slower and weaker", and red blood cell counts had decreased. The weight loss of the animals before death was relatively mild (5-13%). The "histological study" of body organs (apparently limited, however, to a macroscopic examination) clearly demonstrated that "the brain was the site of predilection of the most severe and most irreparable changes" (the italics are in the original text): "fat degeneration" in many brain "ganglia", abnormalities of blood vessels (probably including perivascular infiltrates), and small hemorrhages. These changes were very different from those De Manaceine had observed in animals that died of starvation, in which the brain was "remarkably spared". She concluded that her findings provided "a proof of the great importance of sleep for the organic life of animals equipped with a cerebral system, and also entitle to consider a bad paradox the strange opinion regarding sleep as a useless, stupid and even noxious habit" (Marina Bentivoglio and Gigliola Grassi-Zucconi,"The history of sleep advances. The pioneering experimental studies on sleep deprivation," Sleep, 20, 570-76).