"Six Dao Immortals?" With the question in his heart, the world carefully observed the book in his hand, and then said to himself: "If you are in the period of the Six Dao Immortals, the age in which the author of this book is located is really too long, can a paper book like this really be preserved for so long?" Yes! Wrong! "I opened the writing wheel and was about to explore the world, and I was startled by the microscopic form of the book. The material of this book is beyond the scope of the world's knowledge, it is neither animal skin nor plant fiber. Although the pages of the book appear to be made of plant fibers as seen to the naked eye, these are camouflaged under the microscopic vision of the writing wheel.

"Let me see what this is made of." The world grabbed a corner of the page with its fingers, ready to tear off a bit for study. However, no matter how hard the world tries, it just can't be torn off. It seems that it is in conflict with this book, and the world feels that it must tear it off a little.

"Huh~huh~", the exhausted world lay on the floor. Well, she admitted, she couldn't help the book. However, just because you can't do it now doesn't mean you can't do it in the future. "Hmmm! Miss Ben will let you go first! The world looked at the book in his hand and said secretly.

Wiping a handful of sweat from his forehead, the world returned to the time it was before. The book says that humans have a lifespan of 800 years, but this is only a theoretical limit. In reality, because of natural and man-made disasters, human beings cannot live that long. Among them, the remaining life of human beings in reality is only about half of the original, that is, 400 years old. And the ninja, through the cycle of chakra, established a large circulation system of life in the body. This circulatory system is very powerful, in which the external force of the chakra itself can avoid natural disasters, and the external toxic substances, microbial parasitism, which will damage the body, can be eliminated by relying on the internal force of the chakra. So, as long as the ninja is not killed by other people, then there is no problem in living a life and living a theoretical life.

"Half life?" The world couldn't help but think of the inhabitants of the capital city of the Fire Nation. If you want to do a survey on the current maximum lifespan of human beings, then the old man in the capital city of the Fire Nation is the best target. Although six years have passed, the world's impression of the capital city of the Fire Nation is still somewhat fond, after all, this is the place where the world's first mission is. In the impression of the world, the living conditions of the residents of the capital are still okay, and the elderly can be seen everywhere, but there are still a lot of them.

Then, taking the old man in the capital of the Fire Nation as an example, a human without chakra can live up to about seventy years old in a natural life. Based on the theories in this book, the world deduces that ninjas who have chakra to protect themselves can live up to 140 years old if they are limited to the number of cell divisions.

This conclusion is a bit surprising to the world, but when you think about it, there is nothing surprising about it. In the book, there is another theory that the world is more concerned about.

Generally speaking, the chakra flow speed in a ninja's body is comparable to the flow speed of blood, and the blood flow speed of a ninja is no different from that of a normal person. However, unlike ordinary people, ninjas can speed up the metabolism in the human body by regulating the flow rate of chakra in the body. In addition, while the injured ninja recovers quickly, the chakra will also increase proportionally according to the speed of acceleration. And this approach, for a world that has already developed the Blood Inheritance Limit to half of it, is no problem. However, the essence of speeding up metabolism is to sacrifice the life inherent in the human body. It can be said that this is trading for its own limited future. Of course, this is not a reason for the world to resist. After all, as long as the food can keep up with the speed of metabolism, you won't lose much chakra. However, in the eyes of the world, life is more than just a chakra.

"Whew~~", the world exhaled deeply and looked at the sky outside the window. I saw that the sun had passed the center, and by the world's own inference, it was about three o'clock in the afternoon. So, the world put together this 800-plus page book "The Basics of Medicine". "Is it already this time?" The world was a little surprised at how quickly time passed, then looked at the book in his hand and said, "It's time to return the book." ”

"Kurino-chan, I'm here to return the book!" Outside the door of the medical examination room, the world shook the book in his hand at Kurino Uchiha.

"Eh~! World sauce, are you optimistic about it so quickly? Uchiha Kurino looked very surprised.

"Hmm~, look at it." The world said with a natural expression: "I am a person who has a chakra eye, and I can quickly record the contents of the book. ”

"Whew~!" Uchiha Kurino exhaled, took the book in the world's hand, and said, "World-chan scared me!" I thought you understood the book so quickly. ”

"Got it, is that hard?" The world asked with a confused expression.

"Eh~~~!!" Kurino only felt that he had been hurt by 10,000 points, and the whole person was not good. "The text in this book is written in ninja script, and many of the nouns in it seem to be technical terms, can you understand this?!"

"Uh~", the world was stunned when he heard this, and then opened the "Medical Basics" in his hand and took a look, that's right! Indeed, as Kurino said, it was all written in ninja script. And those nouns that seem to be technical terms, the world can not hesitate to say their pronunciation and meaning.

Suddenly, this matter began to reveal a trace of weirdness.

Ninja writing, is a civilization brought by Kaguya from the big barrel of Jupiter. The original ninja writing came from the Otsuki clan's exploration of runic literature. It has always been the basis for the use of seals by the Otsuki clan. In order to cope with the needs of the Otsumu people for written communication, this rune was used in daily life. And, over time, the writing system has grown stronger. In some ways, it can be compared to the number of words in Chinese. In real-world China, there are about 90,000 characters in Chinese, and more than 7,000 are commonly used. It can be said that the complexity of the Otsuki clan script is far from completely destroying the writing system (Japanese) of the human beings (Hokage) on the earth.

Of course, this is not difficult, the real difficulty is the Six Paths Immortals, the Otsuki Hajiro, who once destroyed many books written by Kaguya in ninja script. This is not only a fault in the use of chakra, but also a break in the transmission of words. It can be said that even the Six Dao Immortals have not learned all the ninja characters. Of all the ninja writings that exist today, it is estimated that only the "Uzumaki" and "Libra" are the most well-preserved.

Of course, the world knows nothing about what happened during the period of the Six Dao Immortals. However, it is indeed a little strange that I have a strange understanding of ninja characters that I have never learned.

"Kurino-chan, then put this book here first! It just so happens that I can translate the contents of this book into ordinary words. In that case, wouldn't you all be able to watch it? The world took back "Medical Basics" without leaving a trace.