It was at the edge of ten that he became sharply aware of the difference in physical appearance between him and the mangani.  He had been ashamed of his hairlessness for a long time, and he hated to be called a tarmangani.  But not until he went to drink one day from a lake in the bush jungle did he realize how ugly his face was.  He was accompanied by a male child of one of Kala's younger sisters and so got a chance to compare his face with his playmate's in the mirrorlike waters.

He became so intent on his distressing comparison that he did not hear Sabor, the lioness, creeping up on them.  A moment later, he was getting his first, and possibly last, lesson in how to swim.  When the lioness, roaring, had sprung on them, she had forced him to dive into the lake. He came up almost at once, and, in an effort to keep his head above water, discovered how to dog-paddle.  His companion was dead, and the lioness was eyeing Tarzan.  Tarzan knew that the big cats could swim, and he paddled away, meanwhile giving the distress cry of the mangani.  The tribe came and chased the killer away.  Thereafter, Tarzan swam frequently whenever he got the chance.  The mangani thought this strange but did not complain.  They were happy because it helped reduce his odor, so offensive to them.  Like most rain-forest creatures, they had fewer sweat glands than the dwellers of the open spaces.  They were also more vegetarian than Tarzan and so did not have essential carnivore's stink.

Shortly thereafter, Tarzan again visited the cabin by the seashore.  This time he found out how to unlock the door, and he entered the world of man.

(He had never entered the storehouse.  It had been hit by lightning, had exploded, and had burned between his two visits.)

In the cabin he found a hunting knife of the best Sheffield steel and a child's illustrated alphabet.  These were the keys to unlock the treasure of his human heritage.At this time, he did not correlate the pictures with the words below.  Indeed, he not only did not recognize the letters as printed symbols for words, he did not recognize the illustrations as such.  He had never seen a drawing before, so he viewed them only as meaningless patterns of color.  But, after a half hour of looking at them, something silently clicked in his mind.  The patterns swam out of chaos to become configurations, some of which he recognized.  This was his first step in his long self-education in reading and writing.  It would be an extraordinary, even heroic feat.  Admittedly, only a genius could have done it.  But Tarzan, as is demonstrated in Addendum 2, belonged to a clan which produced geniuses, both mental and physical.

Looking through the book, he recognized Manu, the monkey, and Numa, the lion, and his old enemy, Histah, the snake.  Even the reptile's picture raised a specter of cold on the back of his neck.