Some Googling revealed that this book is poking fun at The Concord Summer School of Philosophy, which "was hosted in Concord, Massachusetts, by Bronson Alcott on his property. William T. Harris organized the school and its programs...with the intention of unifying the Hegelian Idealism of the St. Louis Philosophical Society with the Transcendentalism of Concord."
The abstract of a paywalled essay sums it up thus: "During its ten summer sessions (1879–88), the Concord School of Philosophy attracted hundreds of attendees who, for intellectual improvement and a glimpse of aging transcendentalists, endured lectures on the classics, philosophy, and comparative religions."
As the Panther notes, these cartoons all retell the same joke: people attend claiming they're seeking knowledge when in reality they're seeking a summer romance.
Link to the book:
Summer School of Philosophy at Mt. Desert