CHAPTER XIII 



AI,GAE IN WATER SUPPLIES 



Algae have long been known to be injurious to water supplies and numerous 

 papers in the United States and Europe have discussed some of the problems 

 arising therefrom. Algae are generally small, microscopic plants found in water 

 and belong to the great class known as Thallophyta. These frequently cause 

 the pollution of water supplies and are therefore of first importance in this 

 connection. Some algae contain a green coloring matter called chlorophyll and 

 hence they are able to make their own food out of water and carbon dioxid. 

 Many of the algae, however, are not green, some being. blue, others red, and 

 still others brown. The Sea Mosses are algae also, and occasionally attain 

 great size and length. Some algae are supposed to be injurious to stock, Mr. 

 George Francis in Australia having attributed a disease of horses, sheep, dogs, 

 and pigs to some blue-green algae. The organism causing the trouble in this 

 case was referred to Nodularia spuntigera, which floats on the water and, being 

 wafted to the lea shores, forms scums from two to six inches thick. He says 

 that, when animals drink the water, it acts as a rapid poison and causes death. 

 It first produces stupor and unconscioueness, the animal falling and remaining 

 quiet, as if asleep, unless touched, when convulsions come on, with head and 

 neck drawn back by rigid spasms which subside before death. This, in sheep, 

 takes place in from 1-6, or 8 hours; in horses, in 8-24 hours; in dogs, in 4-5 

 hours; and in pigs, in 3-4 hours. A post mortem was made on a sheep that 

 had 30 ounces of fresh scum administered by mouth, death occurring in 15 

 hours. The post mortem, 6 hours later, showed that the stomach had none of 

 the green scum left, all having been absorbed; the abdominal cavity contained 

 2 pints of yellowish material; the heart was flaccid with effusion of serum 

 around it ; lungs, liver, kidneys, and brain normal ; dura mater enlarged ; blood 

 of ventricles and arteries black. It was thought that poisoning was due to 

 the decomposition of the algae which smelled like putrid urine, previous to 

 this it had an odor like butyric acid. Account was not taken of the products 

 of decomposition by bacteria. The trouble may have been caused by the poison- 

 ous products of bacteria rather than these algae. This seems not have occurred 

 to Dr. Francis. 



Many of the algae, especially the following, Anabaena, Clathrocystis and 

 bacteria-like Beggiatoa, produce what is known as the working of the lakes 

 and pig pen odors. Dr. Farlow has described these from Massachusetts and 

 Dr. Trelease has described them for the lakes about Madison, Wisconsin. The 

 greenish-yellow scum occurs on the surface of the lakes, especially noticeable 

 during hot weather of the summer. Dr. Trelease says : 



When a lot of it is present, it appears as fine granules suspended in the water, 

 scarcely visible to the naked eye except as they reflect the light, when they call to mind 

 the dancing motes in a beam of sunlight. Under the influence of a gentle, but continuous 

 breeze, these particles are collected into fleshy masses and are driven ashore, so that they 

 accumulate along the margins of the lake, forming a slimy scum, which quickly putrefies, 

 giving off a very disagreeable odor. During this change, its color changes to a decided 



