55o THE POPULAR SCIENCE MONTHLY 



mitting the Piroplasma through its eggs to the young ticks of the next 

 generation. These may feed on healthy animals the next season, con- 

 veying to them the parasites that have been handed down from the 

 mother tick. 



Several similar diseases of cattle occur in other parts of the world. 

 In Africa, related forms of Piroplasma carried by ticks are the cause of 

 redwater, East Coast fever, Ehodesian fever, and in various parts of the 

 world other piroplasmoses have been observed in many animals. 



Spirochetosis in animals, due to organisms similar to those pro- 

 ducing relapsing fever, is well known. The most familiar example is 

 probably a disease of fowls which is carried by Argas miniatus, a com- 

 mon tick which infests these birds. 



Trypanosomiasis is a general term for diseases like sleeping sickness 

 due to trypanosomes and there are many diseases of this type, among 

 which may be mentioned an old-world affection of horses known as 

 Surra; an African one, Nagana, that attacks other domestic animals as 

 well; and a South American type termed Mai de Caderas. Flies are 

 the insects implicated in the transmission of these diseases, mainly the 

 large tabanid horseflies and the smaller stable flies of the genus 

 Stomoxys. Surra was recently introduced into the United States, but 

 was successfully stamped out before it had become established. 



Among bacterial diseases of animals, anthrax may be mentioned as 

 one which is sometimes transmitted by biting flies, the insects acting as 

 mechanical or contaminative carriers only. 



The foregoing enumeration of insect-borne diseases is by no means 

 complete. Indeed, it would be well-nigh impossible to make it so, in 

 view of the rapid strides which are being made at the present time 

 toward a knowledge of these many problems which bear on the question 

 of public health. New discoveries are being rapidly announced in all 

 parts of the world, and while it is difficult to see how the fundamentally 

 important revelations of the past fifteen years can be equalled in the 

 near future, we should be very unwise to predict that they will not be 

 exceeded. 



