[plt-scheme] Doubt in stream-processing in Sec-3.5.2 of SICP

Hi,
 I have a doubt in section Sec-3.5.2 of SICP. There is code to
 generate sequence of integers using stream-processing.

(define (integers-starting-from n)
  (cons-stream n (integers-starting-from (+ n 1))))

(define integers (integers-starting-from 1))

But if I run the above code in Dr Scheme with language set as "Pretty Big"
it runs into infinite loop.
Is is due to applicative order evaluation method?
Can somebody please explain why it is going in infinite loop?

Thanks in advance

-- 
Thanks and Regards
Vinay Sachdev
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