Semi-Centennial Volume. 69 



"It has been observed by the planters that, if there were two broods of 

 gnats occurring within a short time of one another, the second outbreak 

 is not nearly so fatal to the stock as the first one. This is no doubt 

 accounted for by the fact that, after the first attack, the stock becomes 

 innoculated with the poison, as it were, following which they are prac- 

 tically immune to the effect of the bites from the gnats. 



"Weather notes: March 19 was cloudy and cold; strong N. W. wind all 

 day; mean temperature about 38' F. March 20 and 21, clear and cold; 

 temperature in morning, 28° F." 



Mr. Rosenfeld's visit was made in response to a request received 

 March 7, 1908, from Mr. L. S. Frierson, of Frierson, De Soto parish. In 

 his letter, Mr. Frierson reported some personal observations occasioned 

 by a trip which he had taken to the Bayou Pierre on the day before he 

 wrote. Extracts of his remarks are as follows: 



"A mile from the river the gnats were quite bad. But near the 

 river none could be seen. On working about a raft of logs I pulled 

 out old pieces of stuff simply swarming with what I conceived to be 

 buffalo gnat larvae. They would hold onto their homes by attachment 

 at the posterior end of the body and wave about in the water as though 

 they grew out of the stick. But now and then one could be seen to bend 

 over, and, holding on by its mouth, let loose of its tail, which reached 

 around and took a new hold. As soon as it was secure it released the 

 mouth and resumed rythmic motions. The larvae ranged in size from 

 very young to full grown ones. Many cocoons were already empty. I 

 saw a gnat fly off while I held the stick in my hand. I feel sure that 

 the larvae represented mixed broods, since I noticed the first brood in 

 January." 



The specimens obtained by Mr. Rosenfeld are now preserved in the 

 station collection. His report is quoted from the original records on 

 file: 



"Wednesday, March 11, 1908. — Arrived at Frierson, La., yesterday at 

 noon, but rain has so far prevented me from making any field observa- 

 tions on Simulium. In the course of a talk with Mr. Frierson to-day, he 

 told me a very interesting little story, which may be of a great deal of 

 importance. It appears that once, while preparing to treat a mule very 

 much swollen and apparently dying from the attacks of buffalo gnats, 

 Mr. Frierson was compelled to leave the mule on account of a severe 

 thunder storm coming on. After the storm, on going out to haul away 

 what he expected to be a dead mule, much to his surprise he found the 

 animal up again on its feet, and the swelling had diminished by fifty 

 per cent. He decided that the cold water must have saved the mule's 

 life, and began treating all following cases of gnat attack by simply 

 almost drowning the animal in very abundant bucketfuls of water. If 

 a stream were near at hand, he hauled the animal out into it. Mr. 

 Frierson is considered to be quite a stock doctor in his vicinity, and he 

 has treated a number of similar cases since that time. He told me that 

 he had never lost a case of gnat attack when the animal had been 

 properly covered with water. The water .should be applied in an ex- 

 tremely liberal manner, and the man applying it should not allow him- 

 self to desist from the work until a great quantity of water has been 

 applied. 



"March 12. — In company with Mr. Frierson I rode down to a bridge 

 over Bayou Pierre, about five miles east of Frierson. Against the 

 pillars of this bridge (this having formerly been visited by Mr. Dean) 

 a number of logs and branches of trees had been lodged by recent high 

 water and were held thus in the swiftest part of the current. I found 

 no larvae or pupae on any of the very large logs, but several of the 

 smaller branches, which were standing in somewhat perpendicular 



