种痘之时，以天气融和为主，正、二、三、八、九、十月为上，严寒酷暑，均非所宜，必不得已则四、七、十
一、十二，尚可种也。若五月六月，断不可种。又如春应温而反凉，夏秋冬可类推，凡遇天时不正之气，皆不可种。
自小儿生百日后，若形气充实，精神强健，内无痰热食积惊吓所伤，外无风寒暑湿燥火所感，并无疮癞、无瘰
、无胎毒者，便可及时引种。
又儿若面部红润精采，明亮透达，印堂、山根、年寿及眼下口角无青暗之色，两目有神气精光，此皆无病之
儿可种，反是则不可种。
痘种何以自牛而来，前贤欲穷其故，见牛乳旁有青兰小泡，形与痘类，因悟牛之患痘必轻，以之传人，必然
无害，于是按古之针刺法，取牛痘之浆，种人两臂，按穴刺之下苗，旬日果于所刺之处，随出数颗，自灌水至满
浆，以及收痂落靥，无一损伤，无一复出，盖牛土畜也，人之脾属土，以土引土，同气相感，故能取效，然必须
择佳种鲜浆为要。
自刺引之后，并不发热，其初一二日所刺处，常如蚊咬，至
第三四日始露形影，发出痘尖顶脱血迹，第五六日起如小 ，周遭灌水，第六七日水足灌浆，微微觉痒，第八九日
灌浆满足，两腋底微疼，略似结核，头额掌心俱见微热，此周身痘由此出，毒发则火动，正要其元阳运化也，第
九日十日脚外红晕随散，微热必退，浆转黄蜡色，痘心焦硬处变苍而结靥，半月之外，靥落有疤，其靥光泽坚浓，
卷边如小香菰样，细看 内更有几点小 ，居其中间，此种情形齐备，可以告成功矣。
种痘的时机，以天气温和融洽为主。正月、二月、三月、八月、九月、十月是最佳时期；严寒和酷暑都不适宜，如果迫不得已，四月、七月、十一月、十二月还可以接种。如果是五月、六月，绝对不可接种。又如春天本该温暖却反而凉爽，夏天、秋天、冬天的情况可以类推，凡是遇到天时不正之气（气候异常），都不可接种。
婴儿出生一百天后，如果形体和气机充实，精神强健，体内没有痰热、食积或惊吓所致的损伤，体外没有感受风寒暑湿燥火等外邪，也没有疮疡麻风、瘰疬（颈部淋巴结结核）以及胎毒的情况，就可以及时引种。
另外，如果小儿面部红润有神采，目光明亮透彻，印堂、山根、年寿及眼下口角没有青暗之色，两眼有神气精光，这些都是无病可种的小儿，反之则不可接种。
牛痘为何源自牛？前贤想要探究其缘故，看到牛乳旁有青兰色的小泡，形状与痘相似，于是领悟到牛患痘症必然轻微，用它传给人，必然无害。于是按照古代的针刺法，取牛痘之浆，接种于人的两臂，按穴位刺入下苗，十天左右果然在刺处生出几颗痘，从灌水直到满浆，再到收痂落靥（结痂脱落），无一损伤，无一复发。大概因为牛属土畜，人的脾脏属土，以土引土，同气相感，所以能取得疗效，但必须选择优良新鲜的浆液作为关键。
自刺引之后，并不发热。初一二日刺处常像被蚊子咬一样，到第三四天才显露形影，发出痘尖并脱去血迹。第五六日起如小水泡，周围灌水，第六七日水足灌浆，微微觉得痒。第八九日灌浆满足，两腋下微疼，略似结核，头额掌心都见到微热，这是周身痘由此发出的征兆。毒发则火动，正要依靠元阳来运化它。第九十日脚部外侧红晕随之消散，微热必退，浆转变成黄蜡色，痘心焦硬处变苍而结痂。半月之后，痂落留有疤痕，其痂光泽坚厚，卷边像小香菇的样子，细看里面更有几点小水泡居于中间，这种情形齐备，就可以宣告成功了。
When administering variolation, the primary consideration is mild and harmonious weather. The first, second, third, eighth, ninth, and twelfth lunar months are superior; severe cold and intense heat are both unsuitable. If absolutely necessary, the fourth, seventh, eleventh, and twelfth months may still be used for inoculation. However, the fifth and sixth months must strictly be avoided. Furthermore, if spring should be warm but turns cool, this logic applies analogously to summer, autumn, and winter. Whenever there is abnormal qi of the seasons (atypical climate), inoculation must not be performed.
After an infant reaches one hundred days of age, if their physical form and vital qi are substantial, spirit is robust, and they have no internal injury from phlegm-heat, food stagnation, or fright, nor external contraction of wind-cold, summer-heat, dampness, dryness, or fire, and possess no sores, leprosy-like conditions, scrofula (tuberculous lymphadenitis), or congenital toxins, they can be inoculated at the appropriate time.
Additionally, if a child’s face is ruddy with luster, eyes are bright and clear, and the Yin Tang (space between eyebrows), Shan Gen (root of nose), Nian Shou (bridge of nose), areas under the eyes, and corners of the mouth show no bluish-dark discoloration, and the two eyes possess spiritual brilliance, these are signs of a healthy child suitable for inoculation; otherwise, it is contraindicated.
Why did cowpox originate from cattle? Former sages sought to understand its cause. They observed small greenish-blue vesicles near the udder of cows, which resembled humanpox. From this, they deduced that cattle suffering from pox would have a mild condition, and transmitting it to humans would surely be harmless. Thus, following ancient acupuncture methods, they took the fluid from cowpox and inoculated it into the arms of humans, inserting the seed via needle puncture at specific acupoints. Within ten days, several pustules indeed appeared at the puncture sites. From initial fluid accumulation to full suppuration, and finally to crusting and falling off, there was no damage and no recurrence. This is likely because cattle are earth-associated animals, while the human spleen belongs to the Earth element. Using earth to guide earth, and through resonance of similar qi, efficacy is achieved. However, selecting high-quality, fresh fluid is essential.
Following the puncture inoculation, fever does not occur. For the first one or two days, the puncture site often resembles a mosquito bite. By the third or fourth day, the shape begins to appear, with the pox tip emerging and blood traces shedding. From the fifth to sixth days, it resembles small vesicles, surrounding fluid accumulates, and by the sixth to seventh days, the fluid is sufficient for suppuration, accompanied by slight itching. On the eighth and ninth days, suppuration is complete, slight pain occurs in the axillae, resembling small nodules, and slight heat is felt on the forehead and palms. This indicates the emergence of systemic pox. As the toxin manifests, fire moves, relying on primordial yang (Yuan Yang) for transformation. By the ninth and tenth days, red halos around the feet dissipate, slight heat subsides, the fluid turns yellow-wax colored, and the hardened center of the pox becomes grayish and forms crusts. After half a month, the crusts fall off leaving scars. These scars are lustrous and thick, with curled edges resembling small mushrooms. Upon close inspection, a few small vesicles remain in the center. When this condition is fully established, success can be declared.