This well-researched book is an enlightening if somewhat rambling survey of how our treatment of animals has changed over the past century and a half. It is also, frustratingly, a testament to how much has stayed the same.

The story Wasik and Murphy tell begins on the streets of New York, where workhorses forced to haul overloaded carts were routinely whipped by their owners, and dog and cock fights were staged for gambling and entertainment. Such public displays of cruelty offended the new urban elite, who were increasingly taking dogs and cats into their homes as pets. Those who had fought slavery now found other objects for their liberating zeal. The crusade for animal welfare, the authors tell us, was a small part of a larger ethical awakening that swept the nation after its fratricidal bloodbath. Within a year of the founding of the ASPCA, New York state had enacted an anti-cruelty law, and the organization was given the jurisdiction to enforce it. By 1871, Wasik and Murphy write, eight of the nation’s 10 largest cities had their own SPCAs, all of them granted legal powers by their respective states.

No one surpassed Bergh in sheer zeal and theatricality. Daily, the rail-thin son of a German shipping magnate took to the streets of Manhattan to command coach drivers to stop beating their horses, and to haul abusive butchers off to court. The Daily Herald compared Bergh to the inquisitor Torquemada, and cartoonists lampooned the sallow-faced activist with a drooping mustache as a sanctimonious sniveler. By contrast, the New-York Tribune (owned by the vegetarian and reformer Horace Greeley) editorialized that Bergh’s crusade deserved “the approval of all right thinking people.”

The authors dedicate an entertaining chapter to Bergh’s clash with circus magnate P.T. Barnum, who displayed a menagerie of exotic creatures in his American Museum, a five-story emporium in downtown Manhattan, which included hippos and electric eels, assorted snakes, and “the Learned Seals, ‘Ned’ and ‘Fanny.’”

While “Bergh had not ranked animal exhibitions highly, if at all, in his tallies of the worst offenders,” we read, he did draw a line at Barnum’s feeding boa constrictors live rabbits, a display of nature’s innate cruelty that he feared would erode the moral character of the young people who witnessed it. When Barnum went into the circus business after his museum burned down in 1865, Bergh focused on circuses’ mistreatment of animals, objecting to the use of sharpened bullhooks to train elephants. The Barnum and Bailey Circus, he declared, “should not be patronized by respectable and humane citizens.”

Instead of resisting Bergh and his irksome crusade, Barnum shrewdly forged an unlikely friendship with his nemesis and eventually joined the board of his local SPCA chapter in Bridgeport, Connecticut. Whether this marked a sincere late-life conversion or a publicity stunt is hard to say. But Barnum’s public embrace of Bergh and animal rights helped to sway opinion at a critical moment.

Meanwhile, bison were being slaughtered to the edge of extinction on the Great Plains; passenger pigeons, whose massive flocks once darkened American skies, were wiped out in a matter of decades by hunters, as were Carolina parakeets and other birds decimated for feathers to adorn women’s hats. The Audubon Society was established in 1886 to help safeguard imperiled species.

Fashion could be cruel to animals, but so too could science. The authors introduce Caroline Earle White, a Philadelphia Quaker converted to Catholicism. White channeled her religious belief in the sanctity of life to the founding of the American Anti-Vivisection Society, an organization that opposed the testing of animals in laboratories.

The medical establishment of the day fought back. Animal experimentation had produced remarkable benefits, including several lifesaving vaccines developed by the French microbiologist Louis Pasteur in the 1870s and ’80s. However, in less-able hands, the authors point out, millions of animal lives had been needlessly wasted — and continue to be wasted — “to no good end.”

Like so many of the debates initiated by animal activists in the late 19th century, this controversy continues today. Medical experiments, now regulated, are still performed on countless creatures. But a still greater source of mass suffering is the treatment of livestock. Rudyard Kipling, who visited Chicago in 1889, described scenes in the packinghouses where pigs, “still kicking,” were dropped into boiling vats and cattle “were slain at the rate of five a minute.”

The Illinois Humane Society, we read, was co-opted by the burgeoning meat industry. (Beef baron Philip D. Armour was a major contributor and a member of the society’s board of directors.) And while Upton Sinclair’s muckraking novel “The Jungle” brought public attention to the abuses of the meatpacking industry, the Federal Meat Inspection Act, passed soon after it was published, would regulate sanitary conditions in plants but not animal suffering.

Serious efforts to improve the treatment of livestock would have to wait for the animal rights movement spurred by the writings of the Australian moral philosopher Peter Singer during the 1970s and beyond. But the authors remind us that progress has been slow. Sows are still imprisoned in metal gestation crates; chickens are raised so tightly packed together that they can barely turn around. America has more cows and pigs than cats and dogs, we read, but their welfare garners far less attention. And, while we remain focused on charismatic species like polar bears and whales, thousands of others teeter on the edge of extinction.

Yet Wasik and Murphy are finally optimistic that the “circle of our care” is slowly expanding. The question is whether this gradual blossoming of compassion will come fast enough in an era of climate change to save our kindred creatures — and ourselves.

Richard Schiffman is an environmental journalist.