Sentence:  From this account, it will also be evident, that there can be no danger from the <WSD>retropulsion</WSD>, or rather the retiring of prickly heat, except what may arise from the cause that checked perspiration. Many absurd notions have been entertained on this subject, which have really proved prejudicial to health. It hs been very generally supposed, that the matter of prickly heat was highly injurious, and therefore, that the retiring of it into the body was extremely dangerous. 
Meaning of the word marked with <WSD> tags:  (obsolete) Transfer of a disease from an external source to an internal organ.