It’s easy to think we know all there is to know about Sig­mund Freud. His name, after all, has become an adjec­tive, a sure sign that someone’s lega­cy has embed­ded itself in the cul­tur­al con­scious­ness. But did you know that the Ger­man neu­rol­o­gist we cred­it with the inven­tion of psy­cho­analy­sis, the diag­noses of hys­te­ria, dream inter­pre­ta­tion, and the death dri­ve began his career patient­ly dis­sect­ing eels in search of… eel tes­ti­cles? Per­haps you did know that. Per­haps you only sus­pect­ed it. There are few things about Freud—who also pio­neered both the med­ical and recre­ation­al use of cocaine, joined the august British Roy­al Soci­ety, and unwit­ting­ly re-engi­neered phi­los­o­phy and lit­er­ary criticism—that sur­prise me any­more. Freud was a pecu­liar­ly tal­ent­ed indi­vid­ual.

One area in which he excelled may seem mod­est next to his ros­ter of pub­li­ca­tions and celebri­ty acquain­tances, and yet, the doctor’s skill as a med­ical draughts­man and mak­er of dia­grams to illus­trate his the­o­ries sure­ly deserves some appre­ci­a­tion. Freud’s draw­ing received a book length treat­ment in 2006’s From Neu­rol­o­gy to Psy­cho­analy­sis: Sig­mund Freud’s Neu­ro­log­i­cal Draw­ings and Dia­grams of the Mind by Lynn Gamwell and Mark Solms. These are but a small sam­pling of the many works of med­ical art found with­in its cov­ers, tak­en from a 2006 exhib­it at the New York Acad­e­my of Med­i­cine of the largest col­lec­tion of Freud’s draw­ings ever assem­bled, in com­mem­o­ra­tion of his 150th birth­day.

As the title of the book indi­cates, the draw­ings lit­er­al­ly illus­trate the rad­i­cal shift Freud made from the hard sci­ence of neu­rol­o­gy to a prac­tice of his own inven­tion. Cura­tor Gamwell writes, “as Freud focused on increas­ing­ly com­plex men­tal func­tions such as dis­or­ders of lan­guage and mem­o­ry, he put aside any attempt to dia­gram the under­ly­ing phys­i­o­log­i­cal struc­ture, such as neu­ro­log­i­cal path­ways, and he began mak­ing schemat­ic images of hypo­thet­i­cal psy­cho­log­i­cal struc­tures,” i.e. the Ego, Super­ego, and Id, as rep­re­sent­ed at the top in a 1933 dia­gram. Below it, from 1921, see “Group Psy­chol­o­gy and the Analy­sis of the Ego,” a schemat­ic that “attempts to rep­re­sent rela­tions between the major men­tal sys­tems (or agen­cies) in a group of human minds.” And just above, see Freud’s dia­gram for “The Psy­chi­cal Mech­a­nism of For­get­ful­ness” from 1898, depict­ing “asso­cia­tive links between var­i­ous con­scious, pre­con­scious and uncon­scious word pre­sen­ta­tions.”

It is in these late nine­teenth-cen­tu­ry dia­grams that we see Freud make the defin­i­tive move from empir­i­cal­ly observed illus­tra­tions of phys­i­cal structures—like the 1878 “Spinal Gan­glia and Spinal Chord of Petromy­zom” above—to rela­tions between ideas and “con­cep­tu­al enti­ties that have no tan­gi­ble exis­tence in the phys­i­cal world.” That shift, gen­er­al­ly marked by the pub­li­ca­tion of Stud­ies in Hys­te­ria in 1895, caused Freud some unease. “Look­ing back over his career 30 years lat­er,” writes Mark Solms, “ his long­ing for the com­fort­able respectabil­i­ty of his ear­li­er career is still evi­dent.” Even at the time, Freud would write in Stud­ies in Hys­te­ria that his case his­to­ries “lack the seri­ous stamp of sci­ence.” Though his stud­ies of eel, lam­prey, and human brains involved tan­gi­ble, observ­able phe­nom­e­na, he approached the new dis­ci­pline of psy­cho­analy­sis with no less rig­or, stat­ing only that the “the nature of the sub­ject” had changed, not his method.

The draw­ings, writes Bene­dict Carey in the New York Times, “tell a sto­ry in three acts, from biol­o­gy to psy­chol­o­gy, from the micro­scope to the couch.” As Freud makes the tran­si­tion, his metic­u­lous­ly detailed med­ical work, copied from glass slides, gives way to loose out­lines. One draw­ing of the brain’s audi­to­ry sys­tem from 1886 (above) “is as spare and geo­met­ric as a Calder sculp­ture.” Just a few years lat­er, Freud sketched out the dia­gram below in 1894, a schemat­ic, writes Solms, of “the rela­tion­ship between var­i­ous nor­mal and patho­log­i­cal mood states and sex­u­al phys­i­ol­o­gy.” It’s his first pure­ly psy­cho­an­a­lyt­ic draw­ing, sketched in a let­ter to a col­league, Dr. Wil­helm Fleiss.

In the lat­er dia­grams, as we see above, his ten­ta­tive free­hand gave way to type­script and a tech­ni­cal draughtsman’s pre­ci­sion, with some draw­ings resem­bling, in Carey’s words, “the schemat­ic for an air-con­di­tion­ing sys­tem.” Freud seems to com­ment on the archi­tec­tur­al nature of these dia­grams when he writes in The Inter­pre­ta­tion of Dreams in 1900, “We are jus­ti­fied, in my view, in giv­ing free reign to our spec­u­la­tions so long as we retain the cool­ness of our judg­ment, and do not mis­take the scaf­fold­ing for the build­ing.” It’s a warn­ing many of Freud’s dis­ci­ples may not have heed­ed care­ful­ly enough.

Relat­ed Con­tent:

How a Young Sig­mund Freud Researched & Got Addict­ed to Cocaine, the New “Mir­a­cle Drug,” in 1894

Sig­mund Freud Writes to Con­cerned Moth­er: “Homo­sex­u­al­i­ty is Noth­ing to Be Ashamed Of” (1935)

Sig­mund Freud Appears in Rare, Sur­viv­ing Video & Audio Record­ed Dur­ing the 1930s

Free Online Psy­chol­o­gy Cours­es

Josh Jones is a writer and musi­cian based in Durham, NC. Fol­low him at @jdmagness