The bottles come in two sizes for the 7.7cm, one (as shown) for the long model (7.7cm I.F.K Gr), one much shorter for the short projectile (K. GR 16). Either can be found with green glass or white porcelain tops - or bottoms (?), as they sat upside down in the projectiles. There is also a larger size for the 10.5cm, but these were much more difficult to remove intact from the munition and very few are seen.
The chemical is diphenylchloroarsine/diphenylcyanoarsine (DA/DC or Clark I/Clark II). A sternatory agent normally known as either sneezing or vomiting agent. While not very toxic in small doses it is heavy in arsenic, which stays in the system.
The bottles are frequently seen for sale in Belgium or France, Germany reportedly fired 13 million of the clark projectiles (blue cross) during the war. I used to find the bottles occasionally at the monthly show in Arlon, Belgium, but was told by the man selling them that he was no longer emptying them as all of his cats had died. Keep in mind that at many of these small shows in Belgium and France munitions regulations are frequently not enforced, with many of the items being sold by relic hunters with no idea of what they have. I have seen numerous shows where about one piece in ten contained at least live components, some much worse. Use caution.