Februaey 7, 1908] 



SCIENCE 



223 



temperature sufficiently high to destroy the 

 poison if present. 



As regards low temperatures and cold 

 storage effects, the bacteria may remain alive 

 at zero temperatures and below, and even con- 

 tinue to multiply as long as the medium is 

 liquid. But if meat is stored at temperatures 

 low enough to produce a solidly frozen sub- 

 stratum it will keep indefinitely since there 

 can be no bacterial growth or activity in ice. 

 Powls have been found perfectly good after 

 four years storage at — 10° F. But the public 

 prejudice against cold storage products leads 

 the market men to thaw the birds or meat 

 before placing them on sale. This thawing 

 is done by soaking in cold water, and as fresh 

 water is not used for each piece, the water be- 

 comes foul, and well preserved material be- 

 comes infected. Unsold birds or meat, after 

 thawing and hanging in the air for longer or 

 shorter time, are frequently returned to cold 

 storage and re-frozen to keep until the market 

 demands them. Such re-refrigerated stock 

 always shows marked deterioration. By pur- 

 chasing original frozen stock, and allowing it 

 to thaw slowly in the air, the consumer can 

 insure himself perfectly good material at prac- 

 tically no risk of toxic poisons. Soaking 

 frozen stock is always to be condemned. 



In the lengthy discussion it was brought out 

 that pure sepsin always shows the same degree 

 of toxicity, no matter how prepared. When 

 combined with albumen, certain animal and 

 vegetable poisons appear to act more quickly 

 than do their pure toxins. This is true par- 

 ticularly of ophiotoxin or snake venom. Meats 

 and fowl should be placed in cold storage at 

 once after killing, to insure long keeping. 

 But for economical reasons, the animal heat is 

 allowed to dissipate before putting the meat in 

 the cold room. Meats that are " high," have 

 already begun to decompose, but their habitual 

 use appears to render the consumer more or 

 less immune to the effect of toxins. In sup- 

 port of this theory successful experiments have 

 been made to immunize animals against 

 sepsin. 



Following the discussion, a vote of thanks 

 to the speaker, and to the faculty of the Har- 

 vard Medical school for the courtesies extended 



to the section, was passed. The members were 

 then shown through the laboratories and in- 

 spected the equipment of the Chemical Build- 

 ing. 



Frank H. Thorp, 



Secretary 



DISCUSSION AND CORRESPONDENCE 



tower's evolution in leptinotaesa 

 In Science for July 19, 1907, Professor T. 

 D. A. Cockerell gives a very appreciative re- 

 view of Tower's investigation of evolution in 

 chrysomelid beetles of the genus Leptinotarsa, 

 and incidentally points out some defects. 

 Professor Tower's work is of such scope that 

 it seems desirable to caU attention to certain 

 errors and shortcomings which it contains. 

 Above all one misses a clear presentation 

 of the facts upon which the work is 

 built up and which alone can give it stand- 

 ing among scientists. The value of the evo- 

 lutionary discussion, which makes up the bulk 

 of the work, must rest upon the accurate 

 presentation of data and if these data are 

 weak the deductions can not hold. It is my 

 purpose herewith to point out such statements 

 touching upon the biology and systematic 

 aspect of these beetles as seem to me to call 

 for criticism. Even a slight acquaintance 

 with the literature of the subject would have 

 saved Professor Tower from errors which are 

 surprising in a man who claims to have de- 

 voted eleven years to his subject. 



On page 1 is a tabulation of genera and 

 species of Chrysomelini, abstracted from the 

 " Biologia Centrali Americana." Although 

 this purports to include the forms found in 

 " America north of the Isthmus of Panama " 

 the species found to the north of the Mexican 

 boundary, with the exception of a few species 

 of Leptinotarsa, are omitted. Thus several 

 additional genera, and a large number of spe- 

 cies, should be included in such a considera- 

 tion. It is stated that of the 13 genera enu- 

 merated all but Phcedon are peculiar to Amer- 

 ica, while in fact Plagiodera and Melasoma 

 are likewise circumpolar. To these circum- 

 polar genera must be added Timarcha, Ento- 

 moscelis, Prasocuris, Clirysomela, Gastroidea, 

 Gonioctena and Phyllodecta. Professor Tower 



