We can infer the difficulties Hultin might have had to face during finding the viruses from dead and buried bodies lungs tissue
Explanation:
The clause <em>"but logistical and technological limitations of the time period would prove formidable"</em> helps us infer the difficulties and limitations of the time period when Hultin was trying and ultimately successfully found the virus from the lungs tissues of dead and buried human bodies.
Logistical limitations mean the difficulties faced during organization and planning of complex operations/processes.
Technological limitations mean the difficulties because of lack of advanced technology used for collecting the tissues and finding the virus.
Inference is reaching at some conclusion (true or probably true) on the basis of available information and evidence.
