The Tom-and-Jerry shorts were unquestionably, UNQUESTIONABLY, the most violent cartoons of the golden age. I recall reading that, in terms of bashings, stabbings etc. per minute, the Pink Panther cartoons are the most violent, followed (not surprisingly) by the Road Runner - but we know better than to trust such statistics. It's the Tom and Jerry cartoons that make you say "ouch". This is a tame sample, actually, from the days before Tex Avery came to MGM. Orthodoxy (for instance, Leonard Maltin, "Of Mice and Magic") has it that even the cartoons directed by Hanna and Barbera perked up after he arrived, and orthodoxy is correct. This is still a good cartoon. Watch it, and you'll see the violence I'm referring to clearly enough.
It's a clash between two forces that makes Tom and Jerry so bracingly brutal. Firstly, there's the detailed, polished, true-to-Newton realism. That bowling alley floor really is slippery, and the bowling balls really are heavy - one could get hurt playing with such things. Secondly, there's an element's somewhat muted in this pre-Avery cartoon, although it's still there - the hyper-exaggerated, sadistic anarchy which Avery brought over from Warner Brothers, back when that studio really was producing loony 'toons (mostly not very good ones, it must be admitted). Put them together and you have a bowling ball that will go out of its way to injure a cat, as only a cartoon bowling ball could - except that, somehow, it also behaves like a REAL, genuinely dangerous bowling ball. Ouch.
Tom and Jerry were at their best in the years following this cartoon, when the balance between realism and cartooniness was precisely maintained. At some hard-to-pinpoint moment in the 1950s, the realism got lost, and the cartoons became unbalanced in the opposite direction.
Another factor which enhanced Tom and Jerry cartoons, right through to the end, was their uncertainty. Usually, we side with Tom (the cat), who is mean-spirited but at least honest about it - and usually, it's Tom who is roundly walloped. But Jerry rarely emerges unscathed himself (unlike the Road Runner, or that unendurable creation, Tweety Pie). And sometimes, just once or twice, he gets the worst of the exchange. We suspect that Tom will somehow end up losing the battle, but we don't KNOW that he will - which, I suppose, makes his defeat sting all the more.