Polly Pool Seitz (a great-niece of Blanche and a grandaughter of Katherine Fiske) wrote this memory:
"Grandmother Kate (Katherine) and Aunt Gertrude remember very well the sadness over their mother's dying when their baby sister, Blanche was born. The baby also died."
Polly goes on to write that "Kate was eight and Gertrude was six years old." But this is not correct and is apparently based on family notes that Avis died in 1867 instead of 1865. Kate was born in Jun 1859 and Gertrude in Jan 1861. They would have been 6 and 4 when Avis and Blanche died in 1865.