OCIOBEE 19, 1900.] 



SCIENCE. 



585 



also occurs in them sometimes. It is prob- 

 able they have some physiological impor- 

 tance in transferring food from the chalazal 

 portion of ovule to the embryo-sac, es- 

 pecially after fertilization, to the growing 

 endosperm tissue. They persist until the 

 embryo is fully formed and do not elongate 

 (as in Aeonitum) or multiply, but show no 

 signs of degeneration even in the seed. The 

 embryo is very small with heart-shaped 

 cotyledons, and ahypocotyl about one-tenth 

 their length. The suspensor is short, prob- 

 ably only one cell long. The endosperm tis- 

 sue fills the entire embryo-sac, and is full 

 of oil. The only interesting feature of the 

 ovule development in Delphinium seems to 

 be the added arguments in favor of regard- 

 ing the antipodals as of present physiological 

 use, and not as mere degenerating evidences 

 of a tendency to produce spores in tetrads, 

 or as a partial and functional homologue of 

 the prothallus. 



An Attempted Neiv Method of Producing Zygo- 

 spores in Rhizopus nigricans : By Louise 

 B. Dunn. 



The method consisted in cultivating 

 spores of stock material of Rhizopus on a 

 solid nutrient substance in test tubes. The 

 stock material was the sporangial form, and 

 usually produced zygospores in about a 

 month when sown on sterilized bi'ead. 

 But on a mixture of Pfeffer's nutrient solu- 

 tion and enough gelatine to make it stiff at 

 room temperature, the zygospores were pro- 

 duced in from 6 to 10 days. Trial cultures 

 were also made in test tubes kept at 10° C. 

 and in Petri dishes at room temperature, 

 using the mixture as above ; in Pfeffer's 

 solution without the gelatine and on agar- 

 agar. None of these cultures was success- 

 ful, as only sporangia were formed. 



This rapid production of the zygospores 

 could not always be controlled, averaging 

 three times out of five. Experiments to 

 force zygospore formation in wild Rhizopus 



or Mucor have not been successful as yet, 

 but it is hoped that future cultures may de- 

 termine more definitely whether the results 

 are due to confined space and lack of ox- 

 ygen, to temperature conditions or to nu- 

 trient substance used. 



The Composition of Endosperm and Milk of 

 the Cocoanut: By J. E. Kibkwood and 

 William J. Gies. 



The authors supplemented the report of 

 their work previously given before the New 

 York Academy of Sciences (Science, 11, 

 12 ; 951, 1900) , by presenting the results of 

 later quantitative analyses : The following 

 figures represent the average general com- 

 position of the endosperm : "Water, 46% ; 

 solids, 54%. Of the latter 98.1% is organic 

 and 1.9% inorganic ; 43.4% is fat and 21.9% 

 ' crude fiber.' The fresh endosperm con- 

 tains 0.75% of nitrogen, which is equiva- 

 lent to about 4.7% of ' albuminoid.' It is 

 probable, however, that much of the nitro- 

 gen found exists in the form of ' extractives.' 

 General analysis of the milk gave the fol- 

 lowing average data : Water, 95.3% ; 

 solids, 4.7%. Of the latter 88.5% is or- 

 ganic ; 11.5% inorganic. Three dozen de- 

 terminations of gross relationships gave the 

 following average weights and percentages : 



Weight of whole nut, 610 grama. 

 Integument, 170 grams =-- 27.9%. 

 Endosperm, 333 grams = 54.5'/„. 

 Milk, 107 grams = 17.6%. 



The volume of the milk averaged 105 c.c. 



When Increase in Thickness begins in our Trees : 

 By Geo. T. Hastings. Presented by W. 



W. E.0WLEE. 



As far as could be ascertained no special 

 attention has been given to the time when 

 increase in thickness takes place in our 

 trees. One finds only such general state- 

 ments as this.* " The inner portion of 

 any one annual ring ... is formed in 

 the spring ; while the outer portion . . . 



* Sachs, ' Physiology of Plants,' 1887, pp. 162. 



