1893.] MICROSCOPICAL JOURNAL. 355 



umination of Croton water. Brooklyn aqueduct water, etc., bac- 

 teria of the atmosphere, biological analysis of air of hospital 

 wards, class rooms, .etc., disinfectants and filters, bacteriologi- 

 cal tests. 



BIOLOGICAL NOTES. 



How the Rabbit-Plague Came. — In the early settlement 

 of Australia game was plentiful. Kangaroos of many sizes 

 and colors roamed the island-continent. But the game seen in 

 Great Britian was not met there. The English colonists desired 

 some familiar animals. A settler ordered a box of rabbits from 

 England. Three pairs were brought, liberated in the thickets, 

 and admonished to multiply and replenish the earth. On a 

 continent of 2,900,000 square miles they had plenty of room 

 for exercise, enjoyed unrestricted liberty for travel, and were 

 but seLlom seen. So rarely were they visible that they were 

 regarded as curiosities and relics of animal life in the old coun- 

 try. The colonists wished the rabbits to become more com- 

 mon, and did not molest them. Their only enemies were the 

 wild dingoes, the foxes, and other carnivorous creatures. 



The animals made a start in the world, and, notwithstanding 

 their losses by wild dogs and other flesh-eating quadrupeds, 

 began to increase. Their powers of reproduction are well 

 known, and in a few years they began to be observed in various 

 districts. Their numbers made them the object of sport ; guns 

 were levelled at them and dogs were imported and set in motion 

 behind them, but they had come to stay and could not be 

 repressed. 



Blood Coagulation. — Miss Claypole says : From the action 

 of different per cent solutions of the neutral salts MgS04 and 

 Na2 SO4 in relation to coagulation, an essentially diff'erent con- 

 dition is found to exist in amphibian and fish blood from that 

 known to be present in mammalian l)lood. True fibrin forms 

 in the presence of neutral salts in solutions above 5 per cent. 

 The rapidity of formation increases with the strength of the so- 

 lutions, beginning in 6 per cent in six hours and appearing in 

 15, 20, and 25 per cent in thirty to forty minntes. The quan- 

 tity also varies ; in amphibia it increases toward 7 per cent so- 

 lution as a maximum ; afterward a aecrease in quantity is ap- 



