168 | General Notes. [ February, 
MICROSCOPY.! 
FERTILIZATION BY MEANS OF PoLLeN-TuBEs.—Mr. J. Kruttsch- 
nitt, of New Orleans, has been engaged for some years in the study 
of the pollen of flowers, the formation and history of the pollen- 
tube and its relation to the theory that each ovule is fertilized by 
a tube which descends from the stigma, reaches the ovule and en- 
ters its structure through the micropyle. His conclusion that this 
theory is radically erroneous, and that the functions of the pollen- 
tubes need re-examination, derives its force from the fact that, 
being an experienced, cautious and thoroughly capable observer, 
he has enjoyed exceptional opportunities for the study of the sub- 
ject in plants most suitable for the purpose, and that the uniform 
result of his numerous experiments has been contradictory to the 
accepted theory. During the past few years he has examined 
thousands of cases, and has confirmed his observations in some 
500 instances by mounted specimens, which show with great clear- 
ness the facts as they existed at the time of cutting the sections. 
Yet he has seen no pollen-tubes in contact with the ovules, nor 
anywhere near them, though examined during the times when 
fertilization must be taking place, if at all. On the contrary, the 
pollen-tube is always lost sight of near the stigma. The length 
of the style is such in many flowers that the pollen-tube would 
have a long way to travel to reach the ovule, and the arrangement 
of tissue is often such that nature would seem to have placed the 
greatest difficulties possible in the way of fertilization, instead of 
taking such a direct and certain way as would reasonably be ex- 
pected. Mr. Kruttschnitt, therefore, concludes that it is next to 
impossible for fertilization to take place by the pollen-tube coming 
into actual contact with the ovules, and that, in fact, the whole 
ovary is impregnated with the substance of the pollen. He seems 
pollen-tubes. All these features are exquisitely shown in a spe- 
cial box of preparations just contributed to the Postal Club. 
- As to the general proof of the new theory, it must be admitted 
that the evidence is mostly negative, and that negative is at best 
a poor off-set for positive proof. That one man, however capable 
and thorough, has not seen a thing is overbalanced a thousand 
times by the fact that another capable and candid observer has 
seen it. The first may have taken the chances however small, 
which missed seeing that which did exist, the second could not 
really have seen that which did not exist. Still further observa- 
tions, therefore, extending over a greater length of time, will be 
required to shake belief in a theory which has been so long re- 
arded as a fact, and which rests upon the most positive and 
universally believed statements of fact. On the other hand it 
1 This department is edited by Dr. R. H. Ward, Troy, N. Y. 
