Before photography, the only way for scientists to collect information about subjects of their study was, plainly, by pickling them in jars. Or by drying and saving them in little drawers. Or by assembling the skeletons of formerly living creatures, human and otherwise.

Starting in the 1830s with the Musée Dupuytren, Paris, this collection of medical specimens that date back to the 17th century was visited by a plastic surgeon from Philadelphia named Thomas Dent Mütter. The collection of  fetuses in glass jars, wax models, bones and other items jam-packed into glass display cases inspired him to assemble his own collection of medical matter to use as a teaching tool. Photo below © Arne Svenson

While Dr. Mütter became obsessed with the usefulness of these oddities in his medical practice, he also operated during a time when cheap entertainment often involved the macabre. Think circus sideshows with two-headed goats combined with a little sex and gore and you’re onto something.

Dr. Mütter donated his collection of 1,700 objects and $30,000 to The College of Physicians of Philadelphia in 1858, on condition that the College would hire a curator, maintain and expand the collection, fund annual lectures and build a fireproof museum to house the collection.

The collection has grown to include more than 25,000 objects today, including sections of Albert Einstein’s brain.

The Mütter Museum has been the subject of a film by The Quay Brothers as well as series of photographs by Arne Svenson. Its eye-opening collections can now be viewed in an online exhibition that reveals what it means to be human. The Mütter Museum, 19 S 22^nd Street, Philadelphia, PA Info.

Meanwhile in London, the Natural History Museum is home to 450,000 wet specimens that have been collected over a period of more than 300 years. The collection is named in recognition of the work of Charles Darwin and includes items from his epic voyage on HMS Beagle.

New arrivals join the collection all the time, where they mingle with more historic guests, including an 8.62-meter-long giant squid collected by Darwin (below), sea bass collected by Captain Cook in Australia on his Endeavour voyage, and specimens dating back to the 16th century.

The largest specimens (such as sharks) don’t reside in jars; they’re in enormous metal tanks housed in the building’s basement (above). Explore the Tank Room online here. Darwin Centre at the Natural History Museum, Cromwell Road, London Info