Help with error message "serial was not declared in this scope"

Hi all, this is my first day at coding, and my first post here. Hope it is OK. Uno board and IDE ver 1.8.5 Very simple bit of code - the state machine works as expected, and the serial.print "FSM tester" is fine, but as soon as I try to serial print from with the state machine, the compiler has an error ('serial' was not declared in this scope). I have spent several hours looking around this forum and Google, and tried lots of things, all to no avail! Any help would be greatly appreciated. Thanks.

My code

//  modified state machine 29 Mar 2018

int LED1 = 12;
int LED2 = 11;
int LED3 = 10;
int SW1 = 2;
int cnt = 0;
int state = 0;


void setup()
{
  pinMode(LED1, OUTPUT);
  pinMode(LED2, OUTPUT);
  pinMode(LED3, OUTPUT);
  pinMode(SW1, INPUT);
  digitalWrite(SW1, HIGH);
  Serial.begin(9600);
  Serial.println("FSM tester");

}


void loop()
{
  if (!digitalRead(SW1))
  {
    delay(50);
    if (!digitalRead(SW1))
    {
      while (!digitalRead(SW1));
      Statemachine();
    }
  }
  delay(10);

}


void Statemachine()

{

  switch (state)

  {
    case 0:
      digitalWrite(LED1, HIGH);
      delay (1000);
      digitalWrite(LED1, LOW);
      digitalWrite(LED2, LOW);
      digitalWrite(LED3, LOW);
            serial.print("state 0");
      state++;
      break;

    case 1:
      digitalWrite(LED1, HIGH);
      digitalWrite(LED2, LOW);
      digitalWrite(LED3, LOW);
      //    serial.print("state 1");
      state++;
      break;

    case 2:
      digitalWrite(LED1, LOW);
      digitalWrite(LED2, HIGH);
      digitalWrite(LED3, LOW);
      //    serial.print("state 2");
      state++;
      break;

    case 3:
      digitalWrite(LED1, LOW);
      digitalWrite(LED2, LOW);
      digitalWrite(LED3, HIGH);
      //    serial.print("state 3");
      state = 0;
      break;

  }

}

Easy one this:-

  Serial.begin(9600);
  Serial.println("FSM tester");

yet later it's

      //    serial.print("state 1");

Like a lot of cases in programming case matters.

Oh my good lord ! How could I have overlooked that??!! Thanks IanCrowe, you are a complete star ! I feel like I am as thick as a whale omelette for not seeing that.. Really appreciate the quick reply there, karma given. Taa Terry