At the time when I was conducting my research there was no known method for taking the guinea pig's temperature. I demonstrated a technique which is now widely used.

The discovery that I soon made that the guinea pig was also susceptible to infection made it possible for me, from the third year on, to preserve the virus on this animal.

From the practical point of view, the susceptibility to infection of the guinea pig proved to be the most useful step forward. Today, all laboratories use this animal for preserving the virus.

I have a cat. When I was younger, I had a guinea pig.

It did not seem likely that I was destined to undertake research on typhus.

If we pursue this, we would be the guinea pig.