There are many pictorial representations of Maria lactans ranging from an early Coptic tombstone of the nursing Mary (4 c.) to paintings of the same motif reaching well into the seventeenth century. They are particularly numerous during the Italian and French Renaissance and there are famous names like Campin, Van Gogh, Memling, Michelangelo, Coreggio, da Vinci, and Rembrandt, among those who dealt with this motif. The theme faded away in the 17/18 c., not least because of the artistic censorship initiated by the Council of Trent.
Among the many paintings and sculptures featuring Maria Lactans only few (e.g. Campin, Weyden, Fouquet) depict the baby indifferent or recalcitrant (or maybe satiated) with regard to the nursing mother. Religious art, as we know, was frequently motivated by apocryphal literature. We find the 'nursing' theme already in the Protoevangelium of James. We read: "by little and little that light withdrew itself until the young child appeared; and it went and took the breast of the mother Mary." (19.2) The motif was adopted by a number of church fathers, among others by St. Ephrem in his hymns of the Nativity where Jesus' humility ("he sucked Mary's milk") becomes a blessing for all creation ("from his blessings all creation sucks!"). (Hymns of the Nativity, #3)
Against this background information with its positive appraisal of nursing, the interpretation of the baby refusing his mother's milk seems strange if not outrightly inappropriate. Indifference, rather than refusal, would point to satiation, the baby's state of being fed or gratified! But there may be a different explanation. There exists, among the many motifs of Marian art the so-called 'Miraculous lactation of St. Bernard'. The painting depicts the spiritual nourishing of St. Bernard by the milk of Our Lady. This motif is based on one of Bernard's legendary mystical experiences. Praying before Mary's statue he solicits her, "Show yourself a mother" (Monstra te esse matrem), whereupon the statue comes alive and squirts milk from her breast onto Bernard's lips.
A closer examination of the Kermaria statue shows the face of the mother looking straight ahead (not sidewise, looking at the baby!) as if a figure was standing in front of her. Simultaneously, her right hand squeezes the nipple of her right breast, a gesture typical in representations of the lactation of St. Bernard. The general demeanor of the baby could be interpreted as one of surprise and joy: He does not want to get wet, but rejoices in the gesture of the mother to feed others. In other words, the Kermaria sculpture may be one that originally depicted the lactation of a now-missing St. Bernard, or, more generically, suggests Mary's motherly role for all of us.