It is natural to say that it was superstitious to baptize the sick and dying, by sprinkling, if we hold that only immersion is valid baptism.

The sick and dying cannot be immersed; now, is it superstition for a sick person, giving credible evidence of piety, to be admitted into the Christian church, and receive the Lord's Supper?
In order to do this properly, the subject must be baptized; hence, we derive one powerful argument that sprinkling is valid baptism.

Our Lord would never have made the modes of his sacraments so austerely rigid, that the thousands of sick and feeble persons, ministers in poor health, climate, seasons of the year, times of persecution and imprisonment, and all the stress of circumstances to which Christians may be subjected, should be utterly disregarded, and one inconvenient, and sometimes dangerous, form, of applying water, be insisted on, inflexibly, as essential to the introductory Christian rite.

If the early Christians baptized the sick by sprinkling, they of course supposed that it was valid baptism.

If it was valid at all, and in any case, of course it was Christian baptism, even if other modes were most commonly used.
[Footnote 5: See "Coleman's Ancient Christianity," chap, xix., sec.