494 



KEPOR'J' OF STATE GEOLOGIST. 



and their bodies being usually in places where they cannot be easily 

 reached, they decay and produce a very disagreeable odor. Arsenic 

 is not always effective in killing rats. Phosphorus, which is some- 

 times used, is also ineffective unless made very strong, and it then 

 become dangerous to property because it may ignite and start a 

 fire. 



Ferrets and dogs trained to catch rats are often very effective 

 in ridding premises of the pests, but for the person who has no 

 time to train and assist them, they are not usually of great value. 



However, the most effective method of dealing with rats is to 

 construct houses. ])arns and outbuildings so that the rodents can 

 not get into them. The use of concrete for walls and floors, if 

 the walls are put down deeply, will usually keep them out. It is 

 necessary to use a fairly thick layer of concrete and to lay all 

 drains and water pipes in concrete. Ventilators or other openings 

 should be covered with wire netting. The exercise of care in mak- 

 ing buildings rat proof at the time of construction will more than 

 repay the additional cost in actual saving of money, to say nothing 

 of the annoyance it obviates. 



MUS RATTUS Linnaeus. 

 BLACK EAT. 



Mus rattus Linn., Syst. Nat., ed. 10, p. 61, 1758. Evermann and 

 Butler, Proc. Ind. Acad. Sci. for 1893, p. 127, 1894. 



Diagnostic characters. — More slender than the preceding spe- 

 cies; tail longer than the head and body together; color bluish 

 black with little or no brown fur. 



Range. — This was the common rat of Europe in the early his- 

 toric times. It was introduced into America at the time of the 

 earliest settlements and thrived for about two centuries, when the 

 larger brown rat appeared and drove it out. This species probably 

 reached Indiana soon after the first permanent settlements were 

 made and it disappeared within a few years after the Norway rat 

 appeared. Mr. Chansler says that it was last seen near Vincennes 

 about 1.S45. Evermann and Hutler say that Dr. TTayniond in- 

 cluded it in his Franklin County list in 18H9, hut 1 understand 

 that h(^ includes it as an exterminated species. Dr. Plunnner also 

 says that it (lisa|)p(»ar(Hl within a few years after the coming of its 

 larger relative. 



Recently tlic species has Ixmmi found in the Stale again. An 



