...It has been proved that they are thechief means of perpetuating and transmitting bubonic plague andthat they play important rôles in conveying other diseases to humanbeings... 
David E. Lantz 「House Rats and Mice」
...It is the female alone who accomplishes this task, connected with the function of perpetuating the race...
Frédéric Houssay 「The Industries of Animals」
ランダム例文：
vaccinated iceberg diplomats
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