Medical Knowledge class number 2 - The spirometer.
or in my version - better known as the blow job.
this device is used to collect data of vital capacity.
1st you need is the spirometer.. which look something like this..

to prevent from getting hepatitis or whatever sickness u want, disinfect the inlet of the pipe with potassium manganate, KMnO4, the chemical we studied long long time ago..
then, inhale to the maximum,
hold your breath
even eye balls also popping out..

Lastly analyse the data..

& you should get some figure like this for male..
Then, the job is not yet done..
We still need to determine peak expiratory flow rate using peak flow meter..
as if he's going for a real blow job..

& hilary blows it like a trumpet..
Taken using Nokia E66..
Sorry for the poor picture quality