Slide A
At low power, there is sharp demarcation between relatively normal lung and an area of intra-alveolar hemorrhage.

Slide B
Within the area of hemorrhage, there is loss of many of the nuclei that would ordinarily be present within the alveolar septa. (Compare this area with the relatively normal lung on your slides) This is evidence of infarction. The thromboembolus that caused these changes is not present on your slides. Hemorrhage occurs following embolization to the lung when blood flows into the affected parenchyma by way of bronchopulmonary collaterals. If blood flow to the affected area is insufficient to maintain the viability of the alveoli (as occurs when the venous outflow is sluggish), infarction results.