874 



SCIENCE 



[N. S. Vol. XLII. No. 1094 



be followed by a more detailed account of 

 experiments. 



On Ifovember 6, 1915, six specimens of A. 

 punciipennis were allowed to feed on a patient 

 in wbose blood had been demonstrated the 

 gametes of tertian malaria. The mosquitoes 

 had been bred from larvse and before and after 

 the blood meal were given only raisins and 

 water as food. They were kept at room tem- 

 peratiu-e and were dissected and examined in 

 the usual way after intervals of 7 days (two 

 specimens), 9, 18, 20 and 24 days. The first 

 four showed a moderate to heavy infection of 

 the stomach with oocysts. In the one exam- 

 ined on the twentieth day were found mostly 

 rupturing and ruptured oocysts and an intense 

 invasion of the salivary glands with sporozoites 

 — ^the form which is inoculated by the mosquito 

 into the human host. The sixth specimen 

 alone proved to be negative and in this one the 

 condition of the ovaries suggested the explana- 

 tion that this may have been due to the inges- 

 tion of only a small amount of infective blood. 



On a second case of tertian malaria having 

 a much fewer number of gametes, a single 

 specimen of A. punciipennis was fed on 

 November 12. Upon dissection on December 

 2, a light infection of both the stomach and 

 glands was found to exist. 



In each experiment bred specimens of A. 

 quadrimaculatus were fed on the patients as 

 controls and these also showed a high per- 

 centage of infections upon subsequent exami- 

 nations. 



The demonstration that A. punciipennis is 

 an efficient host for tertian malaria does not 

 necessarily indicate that it is an efficient car- 

 rier of other forms of malaria and, in fact, 

 from Hirschberg's results we may anticipate 

 that such is not the case. 



The writer is indebted to Dr. C. 0. Bass 

 and Dr. F. M. Johns of the laboratories of 

 clinical medicine of Tulane University for 

 assistance in the work upon which this state- 

 ment is based and to Mr. F. Knab for the veri- 

 fication of the determination of the mosquito. 



W. V. King 

 BuKEAU OF Entomology, 

 TJ. S. Department of Agricultuee 



TBE AMERICAN ASSOCIATION FOB TEE 



ADVANCEMENT OF SCIENCE 



SECTION G, BOTANY 



PACIFIC COAST MEETINGS 



The following ofi&eers were present: Professor 

 W. A. Setchell, sectional vice-president; Professor 

 L. L. Burlingame, acting secretary. The meetings 

 were held in the Hearst Mining Building, Univer- 

 sity of California, with the exception of the meet- 

 ing on August 4, which was held in the Botany 

 Building, Stanford University. The following 

 papers were read: 



Tuesday, August 3 

 The Embryo of the Gymnosperms : Professor 



John M. Coulter, University of Chicago. 



Attention is called to three features of Gymno- 

 sperms: the proembryo, the archegonium and the 

 cotyledons. 



Proembryo. — The proembryo presents every gra- 

 dation from a tissue completely filling a large egg 

 to such segmentation of the egg as occurs in 

 Angiosperms. This series represents a progressive 

 change extending from the Devonian to the present 

 time. No better example of progressive evolution, 

 or orthogenesis, can be found. The change is due 

 to the fact that wall -formation begins earlier and 

 earlier in the history of the embryo, thus restrict- 

 ing free nuclear division and limiting the amount 

 of proembryonic tissue. The conditions that favor 

 wall-formation and inhibit continued free nuclear 

 division are unknown, but that this phenomenon is 

 a response to some progressive change in condi- 

 tions is evident. 



Archegonium. — A similar series of progressive 

 changes is shown in the development of the arche- 

 gonium, extending from the appearance of arehe- 

 gonia at the full maturity of the gametophyte, 

 through forms in which they appear earlier and 

 earlier in the ontogeny of the gametophyte, and 

 ending with the maturation of eggs at the free 

 nuclear stage, resulting in the elimination of arche- 

 gonia. The conditions for gamete-formation as 

 contrasted with those for vegetative activity, are 

 getting to be known through experimental work. 

 This progressive change, therefore, is to be ex- 

 plained by the gradual earlier appearance of con- 

 ditions for gamete-formation, which in general are 

 conditions of minimum vegetative activity. In all 

 probability, these are the conditions that also 

 favor earlier wall-formation in the ontogeny of the 

 proembryo. 



Cotyledons. — Evidence is now at hand to prove 

 that polycotyledony and dicotyledony are merely 



