Wilhelm His Sr. and the development of paraffin embedding

Abstract

Paraffin histology is one of the most important and commonly-used laboratory techniques in diagnostic histopathology. The discovery of paraffin embedding is often attributed to the pathologist Edwin Klebs. Klebs was following the lead of Stricker, who embedded embryos in a mixture of hot stearin and white beeswax. We show that Klebs experimented with paraffin wax for embedding tumour tissue. But he quickly rejected it as unsuitable because paraffin wax did not infiltrate the tissue. One of Klebs’ correspondents, embryologist Wilhelm His, Sr., learned of Klebs’ experiments and decided to try paraffin embedding. His dehydrated chicken embryos in alcohol, cleared them in lavender oil, and dripped hot paraffin wax onto them. This process allowed His to cut good sections. Here, we have replicated His’s paraffin embedding protocol in order to determine whether His had indeed made the landmark discovery of infiltration embedding with paraffin wax. We followed the protocol that he gives in his 1868 monograph on the early development of the chicken. The protocol described by His failed, in our hands, to yield sections of the quality that he illustrates in his monograph. Typically, the tissue disintegrated when sectioned due to poor infiltration of the wax. Usable sections could only be obtained if His’s protocol was modified by melting the embedded embryos in fresh paraffin wax. One explanation for our findings is that we failed to faithfully replicate His’s protocol. Another is that his protocol was incomplete. We suggest that His is likely to have discovered and perfected infiltration embedding with paraffin wax but did not publish a complete protocol.

The revolutionary developmental biology ofWilhelmHis,Sr.

“…383-384;Hopwood, 1999Hopwood, , 2000Hopwood, , 2002Hopwood, , 2012; those techniques required an unbroken series of sections of consistent thickness. His addressed these problems by developing a protocol for the infiltration-embedding of embryos with paraffin wax (van der Lem et al, 2021). Edwin Klebs had introduced paraffin wax to histology (Klebs, 1867) but soon abandoned it (Klebs, 1869, pp.…”

Evolutionary Changes in Pathology and Our Understanding of Disease

“…In his paper titled "The Etiology of Anthrax, Based on the Life History of Bacillus anthracis," Koch clarified the natural life cycle of Bacillus anthracis and effectively infected an- • Formalin, the current most popular fixative, was discovered in 1893 by Ferdinand Blum (1865-1969), who had placed an anthrax-infected mouse in formalin overnight and observed the hardening of its tissues [38]. Blum later demonstrated that formalin was effective at maintaining the colour and shape of tissues without affecting their microscopic structure [39] Tissue embedding [40] • Salomon Stricker (1834-1898) used a mixture of beeswax and stearin in 1864 to study frog embryos imals with the organism [44]. Koch's next major work in 1880 suggested that tuberculosis was also an infectious disease, a finding which was met with opposition by Rudolf Virchow, who viewed the disease to be a consequence of malfunctioning host cells without external causes.…”

Clearing Properties Between Coconut Oil and Xylene in Histological Tissue Processing

“…18 The change in the appearance of tissue indicates the effectiveness of the clearing process 19 before infiltration. Infiltration eliminates the clearing agent from the tissue 20 by diffusion to enhance impregnation with the most commonly used impregnating medium; molten paraffin wax. 2 The wax, which has diffused into the tissue after replacing the clearing agent, gets deposited in the tissues.…”