132 CARNEGIE INSTITUTION OF WASHINGTON. 



trated sap, with lower freezing-point, than that of the West Indies, and 

 this fact, doubtless, accounts for the circumstance that the Mexican 

 type is the hardier. Dr. Harris suggests that a knowledge of the 

 freezing-point-lowering of the sap of a species of plant would be of some 

 service in predicting abihty to withstand cold. 



A study of the remarkable marine shrubs known as mangrove trees 

 shows that some of them have a high internal pressure — up to 50 

 atmospheres or possibly more. Certain mangroves which live in nearly 

 fresh water have only half of that concentration. Probably it is this 

 capacity for developing a high sap-concentration that has permitted 

 the mangrove to live in salt water. 



TOXIN OF BREAD-MOLD. 



The investigation of the toxicity in the common bread-mold {Rhizo- 

 pus nigricans) carried on in our laboratories in cooperation with the 

 Bureau of Chemistry of the U. S. Department of Agriculture has been 

 brought to a close. An extended report upon the mycological findings 

 has been written up and is now in the hands of the Bureau of Chemistry 

 at Washington ready for publication. Mr. A. F. Schulze, who was 

 employed here by the Bureau of Chemistry as Dr. Blakeslee's assist- 

 ant in this work, has been called to a model food-preserving plant in 

 Brooklyn. 



BIOMETRIC MISCELLANY. 



Dr. Harris has analyzed biometrically certain data on liability of 

 potatoes to disease. The most important conclusion is that varieties 

 of the potato which show more than the average amount of injury by 

 one disease will, on the whole, show more than the average injury by 

 another disease; accordingly, "to a considerable extent, susceptibility 

 to disease is general rather than specific." 



Dr. Harris has reviewed certain extensive data on the number of 

 nipples in Utters of pigs. He finds the variability in this number 

 greater in males than females, as 1.48 is to 1.28. Also the correlation 

 in nipple number between pigs of the same litter is 0.305 ± 0.019. This, 

 as Harris justly concludes, is e\idence of a strong inheritance of nipple 

 number. Still it would be more significant to calculate the correlation 

 inside the litter of some marked excess over or deficiency under the 

 modal number. 



