118 THE AMERICAN MONTHLY [May, 



Diatoms the speaker was positive, after a visit to Prof. S. Lockwood, 

 that his ingenious theory of reproduction by spores is a theory only. 



With regard to the movements of diatoms, Mr. Mann said that he could 

 bring forward nothing but improved hypotheses and unanswered ques- 

 tions. No theory seemed adequate to the case. Even the most popular 

 theory put forward failed to account for some erratic movements in dia- 

 toms, such as the whirling of naviculiE on end, and the running of particles 

 of foreign matter along the raphe in the direction of the motion of the 

 diatom. Both of these conditions were shown with living forms under 

 the microscope. The subject of the preparation of diatomaceous gather- 

 ings was omitted on account of the lateness of the hour. About seventy 

 lantern slides, mostly prepared by the lecturer for the occasion, accom- 

 panied the remarks. 



After the conclusion of the paper by Mr. Mann, the Secretary resolved 

 A. pellucida in Smith's medium by light reflected from the concave 

 mirror, the latter being above the stage, and the cone of light impinging 

 on the cover-glass. The objective used was a -^-^' Hom. Imm. The 

 illumination of the diatom was probably by some sort of internal (total) 

 reflection in the mounting medium, for the front of the objective was 

 too wide and too near the object to allow the light to reach the latter 

 directly. The same resolution can be obtained, using the bull's-eye 

 condenser instead of the mirror. 



January 9, i8go. — The members met, as guests of Mr. H. F. Crosby, 

 at the Montclair Club. The paper for the evening was prepared and 

 read by Dr. Henry Power, the subject being Bacteria. He went into 

 the history of these forms of life from the time when they were first 

 studied down to the present day, and spoke of the labors of most of the 

 prominent bacteriologists, giving the different methods of culture, stain- 

 ing, etc., and illustrated his lecture with a large number of micro and 

 lantern slides. The classification of the different forms was also illus- 

 trated by means of the blackboard. The paper was an excellent one 

 and handled the subject very clearly. 



February 20, — Meeting held at the residence of Dr. Chambers in 

 East Orange. Dr. George S. Allan read a paper in reply to an article 

 by Dr. Jacobs, published in The Microscope last June, said article 

 criticising the experiments of Dr. Miller, of Berlin, upon decaying teeth, 

 and the conclusions at which he had arrived with regard to certain 

 causes connected therewith. 



March <5, i8go. — Met at residence of the President, Mr. J. L. 

 Smith, in South Orange. The subject for the evening was Pus. The 

 members listened to a very instructive and entertaining talk upon this 

 subject by Dr. Stickler, of Orange, who, during the course of his re- 

 marks, referred to the varying opinions of medical men of to-day, nota- 

 bly those of Dr. Paget, the eminent English surgeon, who does not 

 agree with those who hold to the idea that pus cells and white blood 

 corpuscles are identical. The former are larger, denser, and more 

 granular than the latter. Their reaction with acetic acid is different. 

 After treatment, however, their appearance under the microscope is 

 similar to that of the leucocytes. The pus from a healthy person is 

 clear, shining, and yellow, while that from a pyaemic patient will be 

 flattened out or broken down, the cell wall ruptured, and a great deal 

 of granular matter within the cell. In fact, the appearance is similar 

 to that of carious bone. 



