Blood is a connective tissue in which the intercellular matrix, the plasma, is a liquid.
Blood is usually enclosed in vessels lined by endothelium and so the blood, together with the endothelium, lymph and blood-forming tissues, go together to make up the vascular tissues. It is important to your interpretation of this to understand the staining mechanisms involved. Simply put, the stain used here has two components, methylene blue and eosin and is one of the Romanowsky group of stains, Wright's stain . In addition there is a neutral eosin-methylene blue complex which stains such neutral substances as the granules of the neutrophil, a lilac colour. Avoid cells that have been squashed during the preparation and avoid the thick end of the smear, as the cells here are overlapped and distorted.