This is one of the earlier Tintin albums before Herge had developed his full cast of characters (though this cast was regularly being added to with every album released). So far, the only regulars that appear (other than a couple of brief appearances by the Thompson Twins) are Tintin and Snowy, and even here Snowy doesn't seem to talk all that much. However, this is also the first appearance of the South American tinpot dictator General Alcazar and his South American country San Theodoros.
The story revolves around a small statue from a South American tribe that mysteriously disappears from a museum only to be replaced with a fake. It is easily seen that the statuette is a fake because the original has a broken ear (thus the title of this comic). Tintin's investigation into the theft takes him to San Theodoros where he gets himself arrested, but before he is executed, there are a series of revolutions and while drunk and screaming out 'Long live General Alcazar' he is adopted into the regime as the aide-de-camp to General Alcazar.
This begins the rather interesting series of events in this obscure South American country since Herge seems to be suggesting that revolutions occur every other day here, and this does not end until the final album Tintin and the Picaros. Obviously there is some commentary on the nature of many of these South American countries in that they tend to be politically unstable and generally change rulers at the shot of a gun. While it is exaggerated (a lot) it still reflects the instability of the region continent (though one can argue that there are external forces that are actively creating this instability).
Then we have the oil companies who side up with a certain dictator to attempt to squeeze concessions out of them. In this particular comic, there is believed to be oil straddling San Theodoros and its neighbour, and two companies are urging both countries to go to war so as they can gain concessions over the whole region. This is another interesting thing that Herge raises: a lot of modern wars seem to be instigated by corporate interests and it is the profit motives that drive them rather than any noble or just idea. We also see the arms dealer, working for Korupt Arms GMBH (a German company) who goes to the rulers of both countries to sell weapons to them. This stood out to me because shortly Herge was to end up living in Nazi occupied Belgium, and this suggests that the Nazi's were never really into reading because albums such as this could have certainly raised the hackles of Belgium's World War II masters.
This is an okay comic, certainly not one of his best, but then it is still early days in the development of the series. The two gangsters in this comic are actually a couple of nit-wits, they simply have no clue and are bumbling around attempting to find the statuette (and failing abysmally) and to add to this is the colonel turned insurgent that simply cannot seem to do anything right, let alone blow up General Alcazar.