Studying medicine, the armillary sphere is complete.

Over the past year, the health of the Retired Emperor, Li Yuan, had noticeably declined. Li Zhi had attempted to prescribe various medicinal remedies to improve his condition, but none had shown any significant results. Consequently, he decided to visit the Medical Academy to broaden his knowledge, hoping to devise new solutions. He was well aware that the bond between his father, the Emperor, and his grandfather had only recently begun to mend, and his father was currently doing everything in his power to make up for lost time. Thus, Li Zhi was determined to do his utmost to prolong his grandfather’s life.

Just as Li Zhi was engrossed in his reading, a boisterous laugh from Sun Simiao suddenly echoed from outside. Moments later, Liu An lifted the door curtain, and Sun Simiao’s voice followed him in.

"Your Highness, the Prince of Jin, what brings you here today with such leisure that you find time to study medical texts?" Sun Simiao asked.

Li Zhi rose to offer a bow and replied with a chuckle, "If I were to say I missed the old divine physician, would you believe me?"

Sun Simiao shook his head. "I wouldn't fall for your tricks, Your Highness. It is better to tell the truth."

Li Zhi laughed, "I truly did come here because I missed you, old master."

Sun Simiao smiled, "In that case, produce the gift you brought for me!"

Upon hearing this, Li Zhi scratched his head in embarrassment. "I came in such a hurry that I forgot to bring a gift," he admitted with a sheepish grin.

Sun Simiao looked at him with a mischievous glint in his eyes and remained silent. Seeing this, Li Zhi sighed helplessly, "Alright, the truth is that I came to catch up on the lessons I have missed lately."

Sun Simiao chuckled, "I knew you wouldn't visit the temple without a reason."

Li Zhi laughed off his embarrassment and asked, "Have you made any new discoveries recently?"

Sun Simiao stroked his beard and smiled, "I have adjusted some of the prescriptions, and there has been some progress in the extraction of medicinal substances."

Hearing this, Li Zhi asked for a detailed account of which substances had been successfully extracted. Medicinal extraction was a method Li Zhi had suggested to Sun Simiao, primarily to isolate artemisinin and ephedrine—the former for treating malaria, and the latter for coughs and asthma. Li Zhi’s familiarity with these extraction methods was thanks to his biology teacher from his previous life, who had led the class through these experiments, allowing Li Zhi to master the techniques.

However, the achievements of Sun Simiao and his physicians went far beyond these two. They had also extracted compounds from plants like datura and coptis, though the physicians were still researching their specific uses. Li Zhi was not very familiar with these, so he could not offer much insight. Still, since he was there, he didn't want to leave empty-handed. He casually suggested they try researching blood.

Having studied blood during high school, thanks again to his biology teacher, Li Zhi explained the methods for preparing serum and testing for blood compatibility. He even introduced the principle that blood of the same type could be transfused between individuals. This way, soldiers who suffered excessive blood loss on the battlefield could be saved through timely transfusions.

In this era, few soldiers died instantly on the battlefield; most succumbed to infections or blood loss. Before Li Zhi introduced surgical suturing, a soldier with a severe blade or arrow wound could only apply styptic powder and a simple bandage. Without disinfection or sutures, large wounds almost inevitably led to fatal infections. While disinfection and suturing had already significantly reduced mortality, the addition of blood transfusion technology would likely drive the fatality rate of the Great Tang’s soldiers to an exceptionally low level.

The Great Tang’s military was already formidable. If the casualty rate dropped even further, the soldiers would surely fight with even greater ferocity. Thinking of transfusions, Li Zhi’s mind began to race. He decided to return to his estate to assign tasks to Li Yin: to lead a team in producing saline and glucose solutions, and to have the glass workshop craft bottles to store them. He also planned to visit the Directorate for Palace Buildings to find Yan Lide and source suitable animal intestines to create transfusion tubing. With his current knowledge, this was the extent of what he could achieve.

He would have to leave the rest to the scholars at the Medical Academy. After all, the physics and chemistry textbooks he had written were available there, and as long as they had the curiosity to research, they would eventually look through them.

After hurriedly leaving the Medical Academy, Li Zhi promptly delegated these tasks. No sooner had he finished with the medical matters than the teachers he had hired for the children at the relief settlement approached him. They were there for one reason: they disliked teaching the curriculum Li Zhi had compiled. The reason was simple—they held subjects like mathematics, physics, and chemistry in low regard.

This put Li Zhi in a difficult spot. While his curriculum was designed to progress from simple to complex, the children could certainly not master it without proper guidance. Yet, he could not force these teachers, or they would surely rally a group of literati to complain about him everywhere.

Just as Li Zhi was feeling overwhelmed, Yuan Tiangang returned to the Prince’s estate. As soon as he entered, he happily reported, "Your Highness, I have fulfilled my duty. I have successfully cooperated with Master Li to complete the modification of the armillary sphere."

Li Zhi asked with delight, "It was finished so quickly? Have you verified it? How are the results?"

Yuan Tiangang replied, "Your Highness, this new armillary sphere includes ecliptic observation. One can look up to observe the sun, moon, and stars, and look down to see the time increments. It is a vast improvement over those of the previous dynasty."

Li Zhi was thrilled. "That is excellent! Has my father been informed?"

"Master Li may have already seen the Emperor by now," Yuan Tiangang said.

Li Zhi bowed his hands, "Then Master Yuan can rest assured and await my father’s reward."

Yuan Tiangang replied modestly, "I contributed little; the success of this endeavor is entirely due to Master Li's leadership."

Li Zhi waved his hand, "How the credit is distributed is entirely up to my father. Master Yuan need not be so humble." He then added, "Master Yuan, you are highly proficient in mathematics. Would you be willing to condescend to teach some students for me?"

Yuan Tiangang’s return was incredibly timely; with his mastery of mathematics, he would surely be able to guide the children without any issues.

Yuan Tiangang bowed and replied, "I shall do whatever you command, Your Highness."