种痘必资于苗，而苗之所可恃者，在气之相通耳，若遇热则气泄，日久则气薄，
触污秽则气不清，藏不洁则气不正，此蓄苖之法，所以不可不慎也，如遇好苖，须贮
新磁瓶内，上以物密覆之，置于洁净之所，清凉之处，其所贮之苖，在春天者，一月
之痂可种，冬令严寒，四五十日之痂尚可种，盖寒则气收藏，热则气易拽，故时日有
不同也，然于未收苖时，即当先与出痘之家明言其故，使彼乐从，无所疑忌，彼方肯
用心收贮，不致稍有贻误也。
种痘贵得天时，得其时则种，不得其时则不种，夫天时之正，莫过于春，春为万
物发生之际，天气融和，不寒不热，种之则痘自随其气而发生，此正二三月之时所以
可种也，若交夏之后，六阳尽出地上，人之阳气亦皆外浮，暑热烁金，受病者众，斯
时种痘，儿何以堪，此四五六月之时所以必不可种也，至若秋令，天气清肃，收敛之
时，虽遇可种之儿，而无引毒之具，此七八九月之时，势有不能种也，至于十月，名
曰小者，虽亦可种，然斯时寒气固结，纯阴用事，不若俟冬至后一阳鼓动，借其生生
之气，种之甚吉，此十月之所以可种。犹不若十一十二月之尤可种也，然当回种之时
，亦有不可种者，如春应温而反寒，夏应热而反凉，秋应凉而反热，冬应寒而反温，
当其时而非其气，是天地不正之气也，常人感染则成时疫，小儿调理末遑，况敢言种
痘乎，倘或遇此，只宜稍避，俟时气平定再为议种，方保万全，亦有未种之时，天时
甚正，既种之后，忽尔寒暄不时，此又人事所遇不齐，偶而变气，出乎意外者也，则
宜屋中适其寒温顺会天时，常烧辟秽香，饮食起居，更加谨慎，可保无恙，种痘者宜
详审而体察之。
种痘必须依靠痘苗，而痘苗之所以能够被信赖，关键在于气机的相通。如果遇到热天，痘苗的气就会泄散；放置时间太久，痘苗的气就会变薄弱；接触到污秽之物，痘苗的气就不纯正；收藏不洁净，痘苗的气就不端正。这就是蓄苗的方法不可不谨慎的原因。如果遇到好的痘苗，必须储存在新的磁瓶中，上面用物品严密覆盖，放置在洁净、清凉的地方。所储存的痘苗，在春天时，一个月的痂皮就可以用来接种；冬天天气严寒，四五十天的痂皮还可以用来接种。这是因为寒冷时气机闭藏，炎热时气机容易耗散，所以时间长短有所不同。然而，在尚未收取痘苗时，就应当先向出痘的人家说明其中的道理，使他们乐意配合，没有疑虑和忌讳，他们才肯用心收集保存，不至于稍有延误。
种痘贵在顺应天时，得到适宜的时候就接种，得不到适宜的时候就不接种。天时的正道，莫过于春季。春季是万物发生之际，天气融和，不寒不热，此时接种，痘毒自然会随着天地之气而发生。这就是正二月、三月可以接种的原因。如果进入夏季之后，六阳之气全部出于地上，人的阳气也都外浮，暑热灼伤肺金（指呼吸系统或肺部功能），患病的人很多，这个时候接种，儿童怎么能承受得住？这就是四五月、六月绝对不能接种的原因。至于秋季，天气清肃，是收敛的时候，虽然遇到适合接种的儿童，但没有引导痘毒外出的器具（注：此处原文语境可能指缺乏合适的护理或辅助手段，或特指某种引毒工具/方法，依文意译为无引导之具），这就是七八月、九月形势上不能接种的原因。到了十月，称为“小阳春”，虽然也可以接种，但此时寒气凝结，纯阴之气主事，不如等到冬至后一阳初动，借助其生生不息之气，接种非常吉利。这就是十月可以接种的原因，但仍不如十一月、十二月更加适宜接种。然而，在应该回种的时候，也有不能接种的情况。比如春天本该温暖却反而寒冷，夏天本该炎热却反而凉爽，秋天本该凉爽却反而炎热，冬天本该寒冷却反而温暖。当这个时节却不具备相应的气候特征，这是天地不正之气。普通人感染这种邪气就会形成时行疫病，小儿连调理都来不及，何况敢谈论接种呢？如果遇到这种情况，只宜稍微避开，等到气候平定后再商议接种，才能确保万无一失。也有在未接种时，天时很正当，接种之后，忽然寒暖不时，这又是人事遭遇不齐，偶然出现的气候变化，出乎意料之外。这时应当在屋内调节好寒温以顺应天时，经常焚烧辟秽香，在饮食起居方面更加谨慎，可以保证平安无事。种痘者应当详细审察并体会这些情况。
Vaccination (Smallpox inoculation) must rely on the variolous matter (seed), and what makes the seed reliable lies in the communication of Qi (vital energy). If exposed to heat, the Qi will dissipate; if stored for a long time, the Qi will become weak; if touched by filth, the Qi will not be pure; if stored uncleanly, the Qi will not be upright. This is why the method of storing the seed must be handled with extreme caution. When good seed is obtained, it must be stored in a new porcelain bottle, covered tightly with an object, and placed in a clean and cool location. For seeds stored in spring, scabs from one month can be used for inoculation; in winter when the cold is severe, scabs from forty or fifty days can still be used. This is because cold causes Qi to store and conserve, while heat causes Qi to easily scatter, hence the difference in timeframes. However, before collecting the seed, one must clearly explain these principles to the family whose child has had smallpox, so that they willingly comply without doubt or fear, thereby ensuring careful collection and storage without any delay.
The success of vaccination depends on adhering to the appropriate season. One should inoculate when the timing is right and refrain when it is not. The most favorable season is spring, the time when all things begin to grow. The weather is mild, neither too cold nor too hot. Inoculating at this time allows the vaccine to develop naturally in accordance with the seasonal Qi. This is why the second and third lunar months are suitable for inoculation. After entering summer, the Yang Qi of the six channels emerges fully above ground, and human Yang Qi also floats outward. The summer heat scorches Metal (referring to the Lung system), leading to widespread illness. At such times, how could children endure inoculation? Therefore, the fourth, fifth, and sixth lunar months are absolutely unsuitable for inoculation. As for autumn, the weather is clear and crisp, representing a time of contraction. Although there may be children suitable for inoculation, there are no tools to guide the toxin out (or: lacking the means to facilitate the process); thus, the seventh, eighth, and ninth lunar months are circumstances where inoculation is not feasible. By the tenth lunar month, known as "Little Spring," inoculation is possible. However, at this time, cold Qi is consolidated, and Pure Yin dominates. It is better to wait until after the Winter Solstice when a single Yang Qi begins to stir, borrowing its life-generating power, which makes inoculation very auspicious. Thus, the tenth month is suitable, though not as ideal as the eleventh and twelfth lunar months. Nevertheless, even during the period designated for revaccination, there are times when it should not be done. For example, if spring should be warm but turns cold, summer should be hot but turns cool, autumn should be cool but turns hot, or winter should be cold but turns warm. When the season does not match the climate, this constitutes the aberrant Qi of Heaven and Earth. Ordinary people infected by this will contract epidemic diseases. How much less can we consider inoculating children who cannot even manage their daily care? If such conditions occur, one should temporarily avoid inoculation and wait for the climate to stabilize before discussing it again, to ensure absolute safety. There are also cases where the initial timing was correct, but after inoculation, sudden fluctuations in cold and warmth occur due to irregular human circumstances or unexpected changes in Qi. In such instances, one should adjust the indoor temperature to harmonize with the external climate, frequently burn incense to dispel foulness, and exercise greater caution in diet and daily routine to ensure safety. Practitioners of inoculation should carefully examine and understand these factors.