----------------------+--------------+--------------+-------------- MONTH. | +1886.+ | +1887.+ | +1888.+ ----------------------+--------------+--------------+-------------- | | | January | 45,000 | 30,800 | 92,000 February | 15,800 | 6,700 | 40,000 March | 11,415 | 30,900 | 66,000 April | 12,250 | 52,100 | 13,000 May | 4,800 | 2,100 | 1,900 June | 8,300 | 2,200 | 3,500 July | 3,000 | 2,500 | 1,070 August | 6,100 | 7,200 | 3,000 September | 8,400 | 16,700 | 1,740 October | 8,600 | 6,700 | 1,130 November | 56,000 | 81,000 | 11,700 December | 63,000 | 19,000 | 10,600 ----------------------+--------------+--------------+-------------- Again, another example: RIVER LEA WATER COLLECTED AT CHINGFORD Number of Micro-organisms Obtained from 1 cc. of Water. ----------------------+--------------+--------------+-------------- MONTH. | +1886.+ | +1887.+ | +1888.+ ----------------------+--------------+--------------+-------------- | | | January | 39,300 | 37,700 | 31,000 February | 20,600 | 7,900 | 26,000 March | 9,025 | 24,000 | 63,000 April | 7,300 | 1,330 | 84,000 May | 2,950 | 2,200 | 1,124 June | 4,700 | 12,200 | 7,000 July | 5,400 | 12,300 | 2,190 August | 4,300 | 5,300 | 2,000 September | 3,700 | 9,200 | 1,670 October | 6,400 | 7,600 | 2,310 November | 12,700 | 27,000 | 57,500 December | 121,000 | 11,000 | 4,400 ----------------------+--------------+--------------+-------------- "During the summer months these waters are purest as regards micro-organisms, this being due to the fact that during dry weather these rivers are mainly composed of spring water, whilst at other seasons they receive the washings of much cultivated land."--Frankland. Prausnitz has shown that water differs, as would be expected, according to the locality in the stream at which examination is made. His investigations were made from the river Isar before and after it receives the drainage of Munich: