Recursively print in scala
First of all, you are promising to return Int from printSeries. Why? If method is printing, isn't much more natural* to make it return Unit (aka void). This is usually can be done either explicitly 

def printSeries(upTo: Int): Unit = { .... } 


or implicitly: 

def printSeries(upTo: Int) { .... } 


(see, no equals sign in code above).

Next, why do you have explicit doNothing method? I think it would be better to write something like: 

def printSeries(upTo: Int) {
  if(upTo &gt; 0) {
    println(upTo)
    printSeries(upTo - 1)
  }
}


You also might want to place @tailrec annotation to ensure that code will be optimized and won't fail with Stackoverflow at big upTo numbers (if it will and function is annotated compiler will yell on you).

@annotation.tailrec
def printSeries(upTo: Int) {
  if(upTo &gt; 0) {
    println(upTo)
    printSeries(upTo - 1)
  }
}


Finally, generally, it is better to produce sequences and only then make something with them.

P.S. you might better to post questions like this on code review site, not on stackoverlow itself

* there is a good rule in programming to make functions do one thing and be good at it so getXandMakeY usually is bad idea.