136 A. L. HERRERA [august 



it is a mere question of provisions. When the oxidisable ferment is 

 spent, when zymoses decrease, and almost all the material carried from 

 the external to the internal medium is wasted, it is but natural that 

 movements and currents become slower and slower. The organism is 

 then said to be sleeping. And how many degrees there are from the 

 simple yawn and somnolence to the drowsiness of a worn-out and 

 fatigued traveller ! But currents do not cease entirely — death is not 

 the issue. The transport of materials is slowly continued from the 

 digestive apparatus to the recesses of the organism, from the outside to 

 the inside. 



In wakening organisms oxidations increase little by little (just as 

 in Butschli's plasm when heated) ; the current is augmented (as in 

 Herrera's plasm when it receives a slight addition of peptone) ; the re- 

 agents in the laboratory begin to bustle, the forge's reverberations swell, 

 and the hymn of work grows louder and louder until it finally attains 

 the pitch of thunder. Bear this in mind, that the act of waking is a 

 slow one, having many degrees and shades. At the break of day our 

 sleep is light, and we begin lazily to stir ourselves without even open- 

 ing our eyes, whilst we remain fluctuating in a pleasant languor. 



Keep this rule in mind ; whenever there is a cause, be it y, z, or 

 n that modifies nutrition, sleep will increase in the exhausted con- 

 valescent, in the newly-delivered mother, in the child endowed with an 

 exceedingly active circulation, in the inhabitant of the tropics whose 

 salts and water are perpetually drained by the everlasting cupping- 

 glass of climate, in the traveller, in the drunkard, in Butschli's 

 " artificial protoplasm," and in my own when seen under the micro- 

 scope at their respective periods of activity and asthenia, in the glutton 

 who ingests and absorbs large quantities of nutritive material, and in 

 the youth who has provoked great waves of commotion which propa- 

 gate themselves through vast nervous territories. On the contrary, old 

 people and sedentary persons sleep both badly and scantily, as they 

 stand in waiting for death. 



I do not admit, metaphysicians ! the existence of any hard and 

 fast line between sleep, this anaesthetic of life, and waking. I do not 

 believe, vitalists ! that an organism can ever be either completely 

 awake or completely asleep. There is always something living, one 

 organ sleeping and another palpitating. A goose never happens to 

 shut both its eyes at once. My own heart has at no time slept as my 

 brain does ; it hardly ever rests, poor perpetual sentinel ! And you, 

 muscles ? We yawn, wake and work too. There are some dis- 

 inherited, beggared organs sleeping in ascetics. Yet, there is a weak 

 and slow nutritive current even there. 



I deny, then, any hard and fast line ; there are no barriers between 

 sleeping and waking, just as there are no absolutely separated and 

 divided things in nature, whether stars or organisms. 



But the day comes when both the currents and the general 



