176 LIFE S BEGINNING ON THE EARTH 



extract the oil or fat contained in an animal's brain. The 

 difficulty is that brain tissues contain about 90 per cent 

 water. Dr. Telkes removed this by a very careful drying 

 of the fresh brain-substance, using only low temperatures, 

 as heating would have destroyed the enzymes in it, and thus 

 its life-like properties. After the drying process was com- 

 plete, the substance was placed in ether which dissolved 

 only the fat-like material. The ether and the fatty sub- 

 stances dissolved in it were poured off, leaving behind a fat- 

 free material. From this remaining fat-free substance, the 

 portion soluble in water was removed by dissolving it in a 

 salt solution. Dr. Telkes thus obtained two solutions from 

 the original brain tissue. The first solution — in ether as 

 solvent — contained all the fat-like materials of the brain. 

 The second solution — in water as solvent — contained some 

 of the protein material of the brain; moreover those salts 

 were added which are known to be contained in the brain. 



In order to produce microscopic drops of the fresh brain- 

 oil, one single large drop of the first solution is dropped into 

 a glassful of the second. The drop now breaks up to form 

 many tiny droplets. The ether contained in the drops is 

 evaporated by blowing air through the watery solution. 

 The oil-droplets are not visible to the naked eye singly, but 

 they make the water slightly turbid. (Of course, any oil 

 forms droplets in water. The reader may be familiar with 

 the appearance of a glass of water to which he has added a 

 few drops of a mouth wash containing some oil, as many of 

 them do. The slight turbidity indicates the presence of 

 microscopic oil droplets.) 



The single small droplets floating in the water solution of 

 brain substance are then viewed under the microscope. 

 They present a striking appearance; we see that they send 

 out protrusions resembling pseudopodia, move around, and 

 exhibit cell division. The protrusions arc in most cases 

 slender and thread-like. (Fig. 71.) If the droplets float in 



