From Kyoto to Fukui
The first vehicle was a special container he had himself developed: two matching rectangular plates of curved glass that could hold the pus between them. Second, he recruited two pairs of parents with young children for arm-to-arm transfers.
On 11/16, Hakuō began the transfer from Kyoto to Fukui by vaccinating two children from Kyoto. After confirming the development of pustules on their arms, he traveled with the children and their parents to an inn in Nagahama on Lake Biwa--an important way station on the way to Fukui. On 11/22 the children's pustules had ripened, and Hakuō extracted lymph from their arms and transferred it to two children from Fukui, who had traveled to Kyoto for this purpose with their parents. The family from Kyoto then returned home, whereas Hakuō and the second family hiked back to Fukui, making a legendary journey across Tochigi Pass in the middle of a snowstorm [Senkyōroku]. On 11/24, the party reached the highway station of Imajō, where a physician from Fuchū was already waiting with three local children in tow. Hakuō vaccinated one of these children as a back-up. On 11/25, the travelers arrived in the castle town of Fukui, and Hakuō vaccinated further children. He probably used the lymph from the glass container for this as the bodies of the arriving children would not yet have been ready for extraction [Sugihara].
Although arm-to-arm transfer turned out to be unnecessary in this case, it subsequently became the preferred method of transmission, due to its reliability. The author of "Gyūtō Kaihei" (Uncovering Cowpox) from 1852 argued that scabs should only be used in rare cases, for example for long-distance transfers, because they were more likely to result in "false" pocks and did not offer the same degree of protection as direct transmission [Umihara 2014, p. 196].
