138 A. L. HERRERA [attgtist 



Summary (concerning every living thing). 



Nutritive currents are endowed with a very great velocity in 

 active life. 



Nutritive currents (sap, blood, protoplasmic currents) are periodically 

 delayed by the want of the reserves expended during the day, and the 

 result is sleep. 



The same currents may be less active during the day on account of 

 inaction or of some other cause, and the result is somnolence. This 

 may also be ascribed to nervous excitation. 



Currents delayed by the constant action of cold — Sleep in winter. 



Currents delayed by an excess of external heat — Sleep in summer. 



Currents delayed or even utterly prevented by lack of moisture — 

 Latent life. 



General co-ordinated currents definitely stopped by coagulation, 

 poisoning, hemorrhages, asphyxia, etc. — Death. 



An Artificial Schematic Organism. 



The principal varieties of sleep, life, and activity may be illustrated 

 by an organism which I have constructed. It can be modified and 

 perfected in a thousand ways, and several may be brought into con- 

 nection. It consists of a damp chamber bounded by walls of cement 

 and gypsum, or a paste of carbonate of lead and linseed oil (skin) with 

 efferent capillary tubes (excretory apparatus). Between the two glasses 

 and the two partitions there are big drops of Biitschli's cytoplasm or 

 " artificial protoplasm " and water. In the middle stands a digestive 

 apparatus formed of thin caoutchouc or of a snake's lung ; two tubes 

 of glass serve to keep it open at the ends, and it is made narrower 

 in the middle ; it receives food (peptone, water, and some sugar 

 solutions) through one end and expels it through the other. For this 

 purpose the mouth is covered after filling the cavity. The whole is 

 afterwards heated by means of a small oil-lamp, and then cooled or 

 dried, whilst the currents and the osmotic phenomena, the deposits, 

 concretions, etc., are observed. The internal currents and movements 

 are stimulated or paralysed according to the conditions mimicking 

 those called vital. As respiration cannot be imitated, the heat afforded 

 by oxidations may be replaced by that furnished by the small oil-lamp : 

 after all it is exactly the same thing. The two glasses being difficult 

 to unite they may be replaced by Vierordt's glass-box or haemato- 

 chrometer. 



Note. 



In a relatively young country, such as Mexico, investigations con- 

 cerning General Biology are very difficult. Science has fructified here 



