Proceedings of the British Association. 63 



they are examined. Having ascertained the results of acids on 

 the pollen, the author was induced to examine the stigma, and in 

 every case found that the stigmatic tissue gave indications of an 

 acid reaction upon litmus paper. The next question is, in what 

 manner is the fertilizing influence of the male organs communi- 

 cated to the ovale ? After quoting the opinions of Amici, Brown, 

 Fritzche, Corda, Treviranus, Brongniart, and others, the author 

 came to the conclusion that the hoyaux or intestine-like protru- 

 sion from the pollen-grains is the result of the action of acids 

 upon the fluid which contained the fovilla in the pollen-grain ; 

 and he inferred this from the fact that this tube or hoijau is never 

 found when the pollen-grain is placed in water, but is constant 

 when the grain is placed in acid. After describing and explain- 

 ing the anomalous character of the pollen-grains in Orchidaceas, 

 Fumariaceag, Asclepias, &c. the author gave the following con- 

 clusions as the results of his researches. 1. The stigma is inva- 

 riably acid. 2. It is in consequence of this acidity that the pol- 

 len bursts. 3. By the same means the fluid contents of the 

 pollen become coagulated, enveloping the fovilla, and assuming, 

 according to the method of dehiscence, diflerent and very re- 

 markable forms. — The memoir was illustrated by an extensive 

 series of drawings. 



A paper on the Alpaca was read by W. Danson. Since the 

 meeting at Birmingham, about twenty of these animals had been 

 imported into Liverpool. The alpaca is remarkable for its ex- 

 traordinarily long wool, the staples being from twenty to twenty 

 four inches in length. The wool is naturally free from grease, 

 in which respect it differs materially from the sheep, attributable 

 to its not perspiring through the skin, and consequently not re- 

 quiring the artificial protection of smearing with tar and other 

 substances injurious to the wool, as far as the manufacture is con- 

 cerned ; and in shearing, the animal requires no washing prepar- 

 atory to the operation. The alpaca is hardy, flourishing under 

 the line of perpetual snow, in the mountains of the Andes, (Peru,) 

 and has a peculiar coat of silky wool, which proves a complete 

 protection against an atmosphere at all times excessively humid, 

 and against the deluging rain which continues to fall more than 

 four months in the year. The animal is not only capable of un- 

 dergoing great fatigue, but moreover lives on mountain herbage, 

 little better than a kind of withered grass, and in times of scar- 



