Bai hu tang
shi gao 48 zhi mu 18 geng mi 18 zhi gan cao 6
When in cold damage the pulse is floating and slippery, this means there is heat in the exterior and cold in interior, bai hu tang governs.
Bai hu jia ren shen tang
shi gao 48 zhi mu 18 geng mi 12 zhi gan cao 6 ren shen 9
When after taking gui zhi tang a great sweat has issued, there is great vexation and thirst, and the disease is unresolved and the pulse is surging and large, bai hu jia ren shen tang governs.
When tai yang is struck by heat, it is summer heat. When there is sweating and aversion to cold, with body heat and thirst, bai hu jia ren shen tang governs.
For thirst with a desire to drink, with a dry mouth and tongue, bai hu jia ren shen tang governs.
Bai hu tang and bai hu jia ren shen tang correspond with the west, autumn, yang ming and earth.
Yang ming represents dryness in the body. When pathological heat and dryness cause yang qi to rise the closing mechanism of yang ming fails. When yang ming fails to descend a separation of yang and yin can lead to death.
This line from the Shang Han Lun describes the start of the separation of yin and yang.
When in cold damage the pulse is floating and slippery, this means there is heat in the exterior and cold in interior, bai hu tang governs.
The heat in the exterior and cold in the interior is the separation and disease. Yang qi must be present on the surface to support function but not excessively. The interior must be warm for normal function, not cold.
The formula bai hu tang and bai hu jia ren shen tang are both used to treat a yang ming channel pattern and a summer heat pattern.
Yet there is a difference between a yang ming channel pattern and summer heat.
How can one formula treat two different patterns of disease?
By looking at the associated lines in the Shang Han Lun and Jin Gui Yao Lue we see the difference between the key symptoms clearly.
182 Question: What are the outward signs of yang ming disease? Answer: there is generalized heat effusion, spontaneous sweating and no aversion to cold, but aversion to heat.
In a yang ming channel pattern there is aversion to heat.
Chapter 2 Line 26 Tai yang disease with heat stroke is known as summer heat stroke. For sweating, aversion to cold, generalized heat, and thirst, bai hu jia ren shen tang is indicated.
In a summer heat pattern there is aversion to cold.
This illustrates the difference between the two patterns.
In a summer heat pattern tai yang is damaged and yang fails to warm the surface giving rise to an aversion to cold.
In a yang ming channel pattern the heat effusion causes sweating. The excessive loss of fluids causes dryness, which gives rise to more heat. The dryness and heat prevent yang ming from making its physiological descent into the interior. This is dangerous and a high fever can cause death.
One formula to treat them both.
Cooling the heat and replacing the fluids is the key to treatment. Shi gao is pungent cold dispersing of heat. Zhi mu is cool nourishing of fluids. Geng mi replaces fluids of earth. Zhi gan cao is tonifying and nourishing of fluids in earth. The use of ren shen replaces fluids while raising the original qi and gathering qi.
In summer heat patterns earth becomes damp and cold. Which is why there are so many modern formulas that treat summer heat and the pivot of earth.