The Encyclopedia Britannica describes Croton oil as a “poisonous viscous liquid obtained from the seeds of a small Asiatic tree…” Highly toxic and a violent irritant, the substance was once used as a drastic purgative and counter-irritant in human and veterinary medicine, but is now considered too dangerous for medicinal use. Applied externally, Croton oil is capable of peeling your skin off. Taken internally, the stuff may be regarded as the atomic bomb, of laxatives.
The Nazi conquest of Europe began with the annexation of the Sudetenland in 1938, the border districts of Bohemia, Moravia, and German speaking parts of Czechoslovakia. Within two years, every major power on the European mainland was either neutral, or subject to Nazi occupation. France fell to the Nazi war machine in six weeks, in 1940. The armed forces of the island nation of Great Britain were left shattered and defenseless, stranded on the beaches of Dunkirk.
On the Scandinavian Peninsula, longstanding policies of disarmament in the wake of WW1, left the Nordic states of Denmark and Norway severely under-strength, able to offer little resistance to the Nazi invaders.
On this day in 1940, German warships entered Norwegian harbors from Narvik to Oslo, as German troops occupied Copenhagen and other Danish cities. King Christian X of Denmark surrendered almost immediately. To the northwest, Norwegian commanders loyal to former foreign minister Vidkun Quisling ordered coastal defenders to stand down, permitting the German landing to take place, unopposed. Norwegian forces refused surrender demands from the German Minister in Oslo, but the outcome was never in doubt.
Nazi Germany responded with an airborne invasion by parachute. Within weeks, Adolf Hitler could add a second and third scalp to his belt, following the invasion of Poland, six months earlier. The Kingdoms of Denmark and Norway, were out of the war.
Norway was out of the war, but not necessarily out of the fight. A Nazi officer passed an old woman on the street, who complained at his rudeness and knocked his hat off, with her cane. The officer apologized and scurried off. The gray-haired old matron snickered, to herself: “Well, we’ll each have to fight this war as best we can. That’s the fourth hat I’ve knocked into the mud this morning.”
A Norwegian Resistance was quick to form, as patriotic locals united against the Nazi occupier and the collaborationist policies of the Quisling government.
The Norwegian secret army, known as Milorg and led by General Otto Ruge, was at first loath to engage in outright sabotage, for fear of German reprisals against innocent civilians. Later in the war, Milorg commandos attacked the heavy water factory at Rjukan and sank a ferry carrying 1,300 lbs of heavy water, inflicting severe damage to the Nazi nuclear research program.
In the beginning, Resistance activities centered more around covert sabotage and the gathering of intelligence. One of the great but still-unknown dramas of WW2 unfolded across the snow covered mountains of the Scandinavian peninsula, as the civilian-turned-spy Sven Somme fled 200 miles on foot to neutral Sweden, pursued by 900 Wehrmacht soldiers and a pack of bloodhounds.
Operations of all kinds were undertaken, to stymie the Nazi war effort. Some actions seem like frat-boy pranks, such as coating condoms destined for German units, with itching powder. Hundreds of Wehrmacht soldiers (and presumably Norwegian women) showed up at Trondheim hospitals, believing they had contracted God-knows-what kind of plague.
Other operations demonstrate a kind of evil genius. This is where Croton oil comes in.
Norwegian resistance fighters, as dedicated as they were, still had to feed themselves and their families. Many of these guys were subsistence fishermen, and that meant sardines. For centuries, the small fish had been a staple food item across the Norwegian countryside. It was a near-catastrophic blow to civilian and Resistance fighters alike, when the Quisling government requisitioned the entire sardine crop.
The Battle of the Atlantic was in full-swing by this time, as wolf packs of German submarines roamed the north Atlantic, preying on Allied shipping. Thousands of tons of sardines would be sent to the French port of Saint-Nazaire, to feed U-Boat crews on their long voyages at sea.
Norwegian vengeance began with a request to the Special Operations Executive (SOE) in Great Britain, for the largest shipment of Croton oil, possible. The “atomic laxative” was smuggled into canneries across Norway, and used to replace vegetable oil in sardine tins. The plan worked nicely and no one suspected a thing, the pungent taste of the fish covering the strange flavor of Croton oil.
From midget submarines such as the Biber, Hai, Molch, and Seehund models to the behemoth 1,800-ton “Type X“, the Kriegsmarine employed no fewer than fifteen distinct submarine types in WW2, including the workhorse “Type VII”, of which some 700 saw service in the German war effort. In the North Atlantic, the battle raged on with torpedo and depth charge. Under the surface, there unfolded a different story.
Except for the participants in this tale, no one knows what it looks like, when ten thousand submariners simultaneously lose control of their bowels. It could not have been a pretty sight.
Feature image, top of page: “Anti-Nazi graffiti on the streets of Oslo, reading “Live” above the monogram for the Norwegian king, who had fled when the Germans invaded in 1940”. (Photo: Bettmann/Getty Images)