Realy doesnt make since....if it is 250mg/ml (1ml=1cc) that means if you take 1cc(or ml) you are still taking more than the required dosage since it says that you are only to take 200mg. So you would really need to take a little less than 1cc
The minim is obsolete and a slightly different size in US and UK. Rowlett gives the following definition:
minim (m or min) 
a traditional unit of volume used for very small quantities of liquids. In pharmacy, the term drop traditionally meant the same thing as 1 minim. The minim is defined to be 1/60 fluid dram or 1/480 fluid ounce. The U. S. minim is equal to about 0.003 760 cubic inch or 61.610 microliters, while the British minim is equal to about 0.003 612 cubic inch or 59.194 microliters. As you might guess, the word comes from the Latin minimus, small.
This is and can be a very serious subject, 1 ml is equal to 1 cc do not guess call your Dr, Vet, or Pharmacist don't ask these morons who don't know when dealing with such a serious subject as med conversion.
mg is a weight, ml is a volume, so they don't convert.
But usually meds tell how many mg per ml, eg. 20mg/ml, so if you are to give 200mg a week, you would need 10 ml to give you 200mg....and 10ml is the same as 10cc