These claims are all nonsense by the way. Most of these are all viral diseases (and viruses are too small for Roy to have observed in his microscope) and no one today even knows what Roy was observing (in other words, it's not a bacterium modern bacteriologists recognize!).
Anyway, Roy searched for this oscillococcus in other animals and supposedly found it in the liver of a duck that the French know as Canard de Barbarie. Now I fully confess to not understanding the reasoning for this (most like because it's complete bullshit), but homeopathy believes you can start with a source of this bacteria, dilute it down, and then use it to treat the disease.
So what is modern Oscillococcinum you can purchase today? The active ingredients are listed as "200 CK Anas barbariae hepatis et cordis extractum" (obtained from Drugs.com). Inactive ingredients are simply sucrose and lactose (i.e. sugars). I'll explain the 200 CK in a minute, that's the "dosage" (you'll see why I put that in parentheses as well). Anas barbariae is not a species name, anas is simply the Latin word for duck so it's Latin for the French term Canard de Barbarie which is really the Muscovy duck or Cairina moschata. What's hepatis et cordis extractum? It's simply Latin for "extract of liver and heart." So you kill a duck, extract the heart and liver, toss them into a sterile flask with some pancreatic juice and glucose, and let it autolyse (disintigrate into goop) for 40 days. Then you dilute it to 200 CK.
So what's a CK? It's not a standard notation seen in science, it's specific to homeopathy. C stands for centesimal and means a 1:100 dilution and K stands for the Korsakovian method. The Korsakovian method was developed by Semen Nikolaevich Korsakov (no, I didn't misspell his first name!), a Russian bureaucrat in the early 19th century (no medical or scientific training).
Let's imagine we start with a 1 liter flask. In the Korsakovian method, you fill a flask with 99 parts (990 ml) of a diluent (might be water, alcohol, sugar water, etc) and 1 part of your active ingredient (10 ml - about 2 eyedroppers worth). That's a concentration of 1CK. Shake it up good (homeopaths call it "succussion" and sometimes specify 100 shakes). Pour out 99% of the liquid (990 ml) and then refill with your diluent. Now you have a 2CK concentration. Repeat 200 times for a 200CK dosage as found in Oscillococcinum.
Thousands of Americans die from influenza each year. Many of these deaths can be prevented by a simple immunization (the flu shot). This "all natural" remedy is EXACTLY as effective as drinking a glass of sugar water.
By the way, did you hear about the guy who missed his homeopathic remedy dose? He died of an overdose. Get it?