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NEW YORK (TheStreet) -- You can train dogs but you can't herd cats, Jim Cramer told his Mad Money TV show viewers Wednesday as he pondered how the markets that were so loved just a few weeks ago could be so hated this week.

Cramer said it appears the markets got complacent at the end of 2014, shrugging off the bad news and sticking with the notion that low interest rates and low commodity prices will stimulate business activity and boost stocks.

But now investors seems to have traded that lovable old dog for a fickle cat, one that scratches and bites at just about everything. Indeed, the markets now fear low interest rates and commodities as some sort of canary in the coal mine signaling something bad is lurking in the shadows.

Cramer said it makes sense to assume that oil and copper producers will decline in 2015, and that bank stocks will struggle with more lawsuits and regulations. But you can't assume food and drug stocks won't make more money now that commodity prices are lower, or that retail sales won't swoon now that consumers have more money in their pockets.

Cramer said cats have nine lives and tend to reappear when you least expect them, but that doesn't mean that the stock market is coming to an end.

The Macros Behind the Moves

With commodity prices continuing to slump ever lower, Cramer told viewers it's important to understand the macro trends behind these moves because they are big, powerful and likely here to stay.

The first big trend is copper. Cramer said that for the last decade, copper has been driven by one thing -- China, which now accounts for 40% of global demand. But China has slowed -- some would say to a screeching halt -- and that means copper prices are likely headed back to their trend line near $2.

The second trend is hedge funds. Cramer said that in the past hedge funds were diversifying into commodities because they were a red-hot place to be. But with low inflation, commodities aren't in high demand and that means hedge fund buyers are heading for the exits.

The third big trend is oil. Cramer said oil prices have been kept artificially high by OPEC, but now the OPEC cartel is broken thanks to U.S. shale. What is seen as worldwide weakness will eventually be seen as domestic strength. However, for now the world is adjusting to a world where OPEC just doesn't matter anymore.

Cramer said all of these trends are big ones investors should not underestimate. You must get used to these lower commodity prices because they're probably here to stay.

A Monster Stock

When a stock like Monster Beverage (MNST - Get Report) roars higher on an otherwise down day, investors need to take notice, Cramer told viewers. That's why he took a peek under to hood to see what's going on.

It seems that Monster's 4% rally today came on the heels of a bullish analyst upgrade. But didn't Monster also just receive two bearish downgrades earlier this week? Indeed, it did.

Cramer said the bear case for Monster stems from the company moving its U.S. distribution to Coca-Cola's (KO - Get Report) platform, a move the bears think will cause a dip in sales. But that view may be short-sighted, said Cramer. There's a lot of good things happening at the company.

The bulls are actually excited about Coke taking over U.S. distribution, noting that over the long run Coca-Cola is a better operator. Add to that the international potential Coke brings to Monster and Monster could double its international market share.

With U.S. energy drink sales roaring and the potential for Coke to buy a bigger stake in the company, Cramer said that Monster is still a cheap stock, even way up here at 36 times earnings.

Next-Gen Biotech: Esperion Therapeutics

For the next installment of "Biotech, The Next Generation," Cramer spoke with Tim Mayleben, president and CEO of Esperion Therapeutics (ESPR) , a company helping to win the war on cholesterol. Shares of Esperion were up 209% in 2014 and have rallied hard so far in 2015.

Mayleben said Esperion's treatments are aiming to lower LDL cholesterol like a statin but without muscle-related side effects of current therapies. Nearly one in three Americans have high cholesterol, Mayleben said, which means the potential market is over 180 million people in the U.S. alone.

Esperion has been on a fast path of development over the past six years, Mayleben continued. The company expects to begin Phase III testing later this year. With cardiovascular disease still the number one killer in the U.S., Mayleben said he's very excited about Esperion's potential.

Cramer noted that Esperion is a speculative stock but the company certainly has a lot of promise once its treatments come to market.

Lightning Round

In the Lightning Round, Cramer was bullish on Nordic American Tanker (NAT - Get Report) , NXP Semiconductors (NXPI - Get Report) , Cypress Semiconductor (CY - Get Report) , Veeva Systems (VEEV - Get Report) , Adobe Systems (ADBE - Get Report) and Starbucks (SBUX - Get Report) .

Cramer was bearish on Teekay Shipping (TK - Get Report) , STMicroelectronics (STM - Get Report) , Synergy Resources (SYRG) , Papa Johns Pizza (PZZA - Get Report) , Domino's Pizza (DPZ - Get Report) and Tesoro (TSO) .

Next-Gen Biotechs: Charles River Laboratories

In another installment of "Biotech, The Next Generation," Cramer spoke with Jim Foster, chairman, president and CEO at Charles River Labs (CRL - Get Report) , which helps pharma companies accelerate their drug discovery and testing efforts. Shares of Charles River are up 9% since Cramer last checked in back in October.

Foster said Charles River is helping companies make "go, no-go" decisions faster and more reliably and more and more companies are choosing to partner with them every day.

Foster said that while human trials ultimately decide whether a drug actually works and works well, initially there's a lot of modeling and animal testing that is done, and Charles River is one company that helps make the early determinations.

Cramer said Charles River remains a favorite because it participates in the explosion of biotech without a lot of the risk.

To watch replays of Cramer's video segments, visit the Mad Money page on CNBC.

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-- Written by Scott Rutt in Washington, D.C.

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At the time of publication, Cramer's Action Alerts PLUS had a position in SBUX.