Freethinker, socialist, zoologist, and historian of Darwinism, these are the stations of the life, clouded by tragic, of the professor of zoology at the technical college/university of Karlsruhe, Dr. Walther May (1868-1926). He detailed his career/development himself in a biographical sketch (1904, see here), so that the following only took the basic facts from it complemented through other sources for the time reported as well as for his later years.
Address of the author: G. Mayer, Friedrich-Wolff-Str. 77, D-77500 Karlsruhe 1
"It is not up to me [I am not competent enough in order to know whether] to count this work of May as one of the best that has been published in recent years among the literature on corrals. The description of the forms are exact, as I could convince myself though examinations afterwards [after reading May]. These works are especially valuable, however, because of the open perspective of the author and his ability to derive general conclusions from the found specific facts. The literary ability of Dr. May is beyond question and his special peers will be glad if he could continue to be active in this line of science."
May did not receive the announced title until 1.7.1905. Nüsslin had still praised his protégé shortly before, on 26 May, as follows: "As a highly talented teacher, Dr. May fulfilled his lecturing tasks with great zeal and success. He also distinguished himself as a writer, lately in historic-biographic research, and especially as a brilliant speaker, also outside of the university.""The great interest that you maintain in your former students gives me the hope that you will receive the following lines kindly, as they concern the sorely "tried" Walther May. I, indeed, have some scruples concerning May. I am not sure whether the development he is now going through is the most desirable for him. After all he is my assistant and I am responsible for his zoological education to some extent.There can only be a limited area of zoology for him in Karlsruhe, that of applied zoology.He now reads forest zoology of mammals and birds, where the life of the animals is the main issue, of course. He takes no pleasure in my newer researches on plant-lice, which provide so many points of contact to fundamental/basic zoology and contain difficult problems/issues. Neither in histological or anatomical works. Even less he will learn to study the life and goings-on of animals in the wild outside. I repeatedly called his attention to the voices of our birds, but I doubt that he managed to distinguish blackbirds from thrushes by their song. His skill lies in a different area.I paved his ways here out of interest in his career and esteem for his striving, also out of sympathy for the whole person. I initially arranged that he can show his eloquence in the Natrurw. Verein and to impress his colleagues in that way. I then pushed and carried through his habilitation. Fortunately, the minister of state, Nokk, still lived back then, permeated, as he was, with the spirit of Goethe. To him [Nokk] I presented his [May's]
past and received his consent in the habilitation in turn.Thereafter, it was not very hard to also overcome the difficulties within the senate that were not very grace anyway. The colleagues here are far more liberal in these matters than in the old university. They showed a warm interest in May.
I arranged that he be consigned for the zootomic course and the forest zoology of mammals and birds and he receives 700 Marks for these teaching assignments. furthermore, I procured the 2-hour course for presentations/talks/lectures on general scientific subjects in the summer and winter session. HE lectured on evolutionary theory this summer and on exploratory voyages concerning the geographical sciences last winter. He receives 800 Marks for these. His position as an assistant earns him about 3000 Marks. As pleasant as it is to have achieved so much in three years, both in pecuniary matters and in the widening sphere of influence, it is not a life for good/long term. He does not advance zoologically in this way. His talks consume so much time that even his ironclad diligence cannot find any free minute for research in the institute.
In my opinion, there are only two alternatives, either to step out of the previous or to stop continuing the apprenticeship as a "zoologist" according to the traditional habit, because May cannot become a "zoologist" in this way, neither for a university nor for an institute of forestry.
If he was to step out of his previous career, this would be hard for May and only be possible with the help/interest of one of his previous teachers, who could provide a livelihood as an assistant for him.
If, as he seems to like best, he refrained from becoming a "zoologist" as a researcher in the common sense, that is, refrain from any position as a later professor, he could earn a living and achieve a distinguished position due to his exceptional abilities as a speaker and writer. He actually now develops into this direction. His eloquence procures him ever new opportunities for earning money. I also acted for him in this direction and asked the feuileton editors of the Frankfurter Zeitung whether May could get a chance for a public talk next winter. Maybe you will also have an opportunity to act into this direction in Frankfurt. He will probably soon get the title außerordentlicher Professor [reader/ nontenured lecturer/ extraordinary professor] in Karlsruhe. He will not be able to stay assistant forever and the teaching assignments are revocable."
The principal and senate of the university also recommended the awarding commenting that the lectures, which May had held so far, had proven popular with the audience. The difficulties that had to be overcome for awarding May the title of an extraordinary professorare documented in a letter of Nüsslin to Haeckel written on 31 December:
"May has now become a titular professor (extraordinary/ non tenured), but it took effort, because our old miniter of culture, Nokk, a liberal admirer of Goethe, has since died, and the new one initially did not want to mention the issue to the Gand Duke. DEtailed information about the Cimina of May did, however, change his mind and he told me that the Gran Duke was willing to award the title as soon as he heard of the case. The minister also mentioned that May would have faced no more than six weeks of inprisonment for such writings in Baden, instead of 1 year and 1/4 in Sachsen."
"The Senate met yesterday and we discussed the question whether May could be suggested as a replacement for a librarian who had gone, your current colleague Haussner. The majority was decidedly in favor of this and there is no obstacle from the side of the university. However, the responsible referent [head of division] at the ministry thinks that he cannot be made a civil servant because of the past incidents. I was successful in pushing his nomination as a professor ahead vis-á-vis the new minister of cultural affairs, v. Dusch. On that occasion, I also emphasized that Grand Duke Karl Alexander pardoned May upon your petition. Our GRand Duke was immediately willing, as the minister told me later, and showed a sort of warm interest. Maybe I will again visit the minister and I would like to be able to tell him that you were delighted about the liberality of Baden. Though the minister of culture may shudder at your name, such an appreciation from your side will not fail to have the desired effect."
"We do not only think differently, but we also feel differently. You feel nationally, I do internationally. I am a born cosmopolitan. I already felt uncomfortable at school, already, when the doctor spoke of the hereditary enemy, when Kröner's words were declaimed: "You shall plunge the steel in the enemy's heart." Today I can still not rid myself of this discomfiture, when the flags fly on the occasion of a victory or even the bells of the Christian churches toll... An unbridgeable gap divides us in matters of worldview. But as humans we can extend our hands brotherly across this chasm."
"He started an earnest love relationship with an indeed decent needlewoman and did not think it necessary to keep this relation a secret. This, of course, left no good impression among the wives of the professors. Additionally, it became apparent that several young girls of very good families with considerable dowries had fallen in love with the lecturer with the interesting head and the holy fire. But May had already given himself away. It's a pity that he is such an oddball, whom one can help so little."
"What will further become of May is hard to tell, because he wants to marry a simple girl (needlewoman in job). If this was not the case, I would not worry about his future, as there is quite a number of young ladies in best positions that have fallen in love with his beautiful head and mind. Alas, he has so many inexpedient instincts and habits."
"Maybe you'd be interested to learn that I married on 26 September last year after a mere 19 years of engagement. Hitherto, the circumstances and social prejudices did not allow a marriage, because my wife is a garment-worker. I could only marry her, if she did not give up her occupation, because my circumstances did not allow me to feed a woman. We now used the war-situation to take the long planned move and the upheavals following the war were in favour of our marriage. Nobody now takes umbrage in the fact that my wife has to earn her living as a needlewoman."
The married couple had been living in very poor conditions as May also had to support his mother for many years with his meager income. Even the costs fro May's funeral had to be payed from the coffers of the senate. His widow, completely penniless, was dependent on public welfare.
 May had two siblings, a brother Arthur, born on 14.9.1869 in Wetzlar, deceased as retired major on 14.6.1939 in Göttingen and a sister Klara born on 19.1.1871 in Wetzlar, deceased on 19.4.1932 in Kampen/Sylt.
 For example, a party member from Chemnitz wrote to him: "When someone fought for a higher cause with such a great zeal as you did, he cannot suddenly change his mind. Whatever they may have promised you, nobody can give you back your political credibility nor replace it. I can imagine what influence you succumbed to. But neither you nor the people who turned you into what you are now will have any delight in you." And Heilmann (1912) even wrote: "May later served the clerics; where he perished is unknown."
 Willy Georg Kükenthal (1861-1922), director of the Zoological Institute and Museum in Breslau.
 Wilhelm Nokk (1832-1903), Baden state minister.
 For example, May wrote to Haeckel on 15.2.1903: "I am extremely busy mainly through many talks in various societies. Currently I give a series of lectures on Darwin's life and theory in the local education association. When I gave a talk in Pfortsheim the other day, I also presented some leaves from your Art Forms of Nature and the local jewelers were delighted to find pattern in them for excellent models, which they are often lacking.
 He also offered to give talks, for example, in the journal "Der Monismus" (3, 434, Berlin 1908):
"Mr. Professor Dr. W. May, Professor for zoology at the polytechnic university in Karlsruhe i. B., is willing to give talks in our local associations during the months January to March 1909: 1. On Heredity. 2. My Voyage to the Canary Islands in Winter 1907/08. 3. Charles Darwin's Life and Work. The latter is particularly suitable for Darwin centenary celebrations. Remuneration for Karlsruhe 50 Mark, abroad 100 Mark plus travel costs.
 Karl Hermann HAUSSNER (1863-1948), Prof. for Mathematics at the TH since 1904.
 Alexander Freiherr von Dusch (1851-1923), Baden State minister.
 Incomprehensible error of Nüsslin, a Grand Duke Karl Alexander never existed, back then Grand Duke Friedrich I. (1826-1907) ruled since 1856.
 The announcement of the talk in the association's journal „Nach der Schicht" [After the Shift] says: „The visitors will be administered a printed summary of the lecture at the entrance." This is the title number 38 in the list of Walther May's works.
 On 2. February May announced a lecture he would give on 10th February in the Narural Science Association of Kassel on the occasion of the 100th birthday of Darwin. Since the proceedings of this association do not contain a reference to it, the lecture seems to have been cancelled for unknown reasons.
 A condition of the heart became noticable early on in his life. On 16.2.1904 he already wrote to his mother: "My heart is still the old issue, I can hardly resolve to visit a physician because I would probably not heed his advice anyway." And two days before his death to his brother: "It is really as if all evil spirits had conspired against me, that my condition, which used to be tolerable, suddenly worsened so much: the pains are simply terrible, and who never had them cannot imagine how atrocious it is."
 On 6.12.1925 he wrote to his brother: "Concerning family research, I have set up a genealogy of a great grandfather of Christel that is almost 3 meters wide and contains 81 persons excepting the in-law spouses. However, a whole female lineage is still missing, about which Christel knows nothing concrete. Otherwise the genealogy would be much wider still."
List of Walther May's works [Schriftenverzeichnis]:
1.Ueber die Beobachtung des Ameisenlebens. - Isis. Zeitrschr. f. alle naturw. Liebhabereien, 11, 289-290, 298-300, 306-307, 314-315, Magdeburg 1886, 12, 20-21, 1887.
2.Ueber Kants philosophischen Entwurf „Zum ewigen Frieden". - Menschenthum. Sonntagsblatt für Freidenker, 17, 181-182, Gotha 1888.
3.Glaubensbekenntnis eines Wahrheitsfreundes. Kassel 1889.
4.Charles Darwin über den Instinkt. - Menschenthum, 18, 77-78, Gotha 1889.
5.Schillers akademische Antrittsrede. - Menschenthum, 18, 93, Gotha 1889.
6.Die franzöischen Freidenker des 18. Jahrhunderts. - Menschenthum, 18, 105-106, 109-111, 113-114, 117-118, Gotha 1889.
7.Die Bedeutung der Nahrungsmittel für die geistige und sittliche Erziehung des Volkes. -Menschenthum, 18, 157-176, Gotha 1889.
8.Noch einmal die Nahrungsmittel. - Menschenthum, 18, 175-176, Gotha 1889.
9.Zum 17. und 23. Juni 1899. - Freie Glocken. Beiträge z. Förderung der Vernunft und Humanitäts-Religion, 15, 93-94, Leipzig 1889.
10.Zum 14. Juli 1889. - Freie Glocken, 15, 109-110, Leipzig 1889.
11.Zum 4. August 1889. - Freie Glocken, 15, 121-122, Leipzig 1889.
12.Die Bestrebungen des Deutschen Freidenker-Bundes. - Menschenthum, 19, 1-2, 5-6, 9-10, 13-15, 17-19, Gotha 1890.
13.Natur und Geisteswissenschaft. - Menschenthum, 19, 82-84, Gotha 1890.
14.Der Kampf um den Achtstundentag. - Festschrift zum 1. Mai 1890. Leipzig 1890.
15.Die deutschen Buchdrucker in ihren Kämpfen gegen das Kapital. - Berliner Arbeiterbibliothek, 14, 40 S., Berlin 1891.
16.Die von Dr. Stuhlmann im Jahre 1889 gesammelten ostafrikanischen Alcyonaceen des Hamburger Museums. Inaug.-Diss. Jena. - Jahrb. Hamburg. Wiss. Anst., 15, 1897, 2. Beiheft, 38 S., Hamburg 1898.
17.Alcyonaceen von Ostspitzbergen. Nach der Ausbeute Prof. Willy Kükenthal's und Dr. Alfred Walter's im Jahr 1889. - Zool. Jahrb., 11, 385-404, Jena 1898.
18.Alcyonarien. - Ergebnisse der Hamburger Magalhaensischen Sammelreise. 4. Lfg., 22 S., Hamburg 1899.
19.Beiträge zur Systematik und Chorologie der Alcyonaceen. - Jenaische Zeitschr. f. Naturw., 33, N. F. 26, 1-180, Jena 1899.
20.Ueber das Ventralschild der Diaspinen. - Mitt. Naturh. Mus Hamburg, 16, 143-147, Hamburg 1899.
21.Ueber die Larven einiger Aspidiotus-Arten. - Mitt. Naturh. Mus Hamburg, 16, 149-153, Hamburg 1899.
22.Die arktische, subarktische und subantarktische Alcyonaceenfauna. - In: RÖMER, F., Fauna aretica, 279-403, Jena 1900.
23.Goethes Verhältniss zur Natur und ihrer Wissenschaft. - Verh. Naturw. Ver. Karlsruhe, 13, 524-550, Karlsruhe 1900.
24.Goethe und Alexander von Humboldt. - Verh. Naturw. Ver. Karlsruhe, 14, 3-30, Karls-ruhe 1901 (Besprechung: S. 6"-7").
25.Humboldt und Darwin. - Preuss. Jahrbücher, 105, 241-257, Berlin 1901.
26.Erasmus Darwin, - Verh. Naturw. Ver. Karlsruhe, 15, 117-138, Karlsruhe 1902.
27.Die neueren Forschungen über die Bildung der Korallenriffe. - Zool. Centralbl., 9,1-17, Leipzig 1902.
28.Jean Lamarck. - Verh. Naturw. Ver. Karlsruhe, 16, 125-137, Karlsruhe 1903.
29.Goethe - Humboldt - Darwin - Haeckel. 4 Vorträge, 255 S., Berlin-Steglitz 1904. Neue Ausgabe 1906. (Besprechung von BENEDIKT in der Wiener neuen freien Presse u. in der Frankfurter Ztg.).
30.Darwin im Spiegel meines Lebens. - Verh. Naturw. Ver. Karlsruhe, 17,1-32, Karlsruhe 1904 (Besprechung: S. 6*).
31.Die Ansichten über die Entstehung der Lebewesen. III. - 64 S., Karlsruhe 1905, 2. Aufl. 81 S., Leipzig 1909.
32.Darwinistische Probleme in der griechischen Philosophie. - Verh. Naturw. Ver. Karls-ruhe, 18, 154-204, Karlsruhe 1905.
33.Schillers Verhältnis zur Natur und ihrer Wissenschaft. - Preuß. Jahrbücher, 123, 451-462, Berlin 1906.
34.Zur Geschichte des Großh. Bad. Naturalienkabinetts in Karlsruhe (1751-1878). - Verh. Naturw. Ver. Karlsruhe, 19, 1-19, Karlsruhe 1906.
35.Auf Darwins Spuren. Beiträge zur Biographie Darwins IV. - 63 S., Brackwede 1907.
36.Die Naturteleologie und Biogenie der Kirchenväter. - Verh. Naturw. Ver. Karlsruhe, 20, 33-64, Karlsruhe 1908.
37.Erinnerungen an Rudolf Burckhardt. - Mitt. Gesch. Med. Naturw., 7, 357-362, Hamburg u. Leipzig 1908.
38.Über Vererbung. - 4 S., Kruppscher Bildungsverein Essen v. 23. 1. 1909.
39.Festvortrag am 5. 2. 1909 in Berlin zu Darwins 100. Geburtstag (Kurzfassung). - Mitt. Gesch. Med. Naturw. 8/4, 365-368, Hamburg 1909.
40.Die Darwin-Ausstellung in der Techn. Hochschule Karlsruhe. - Pforzheimer Freie Presse v. 2. 4. 1909; Die Darwin-Ausstellung in der Techn. Hochschule Karlsruhe. -Bad. Landeszeitung v. 3. 4. 1909; Die Darwin-Ausstellung in der Techn. Hochschule (gekürzt). - Bad. Presse v. 6. 4. 1909.
41.Alexander von Humboldts Bedeutung für die Naturwissenschaft. - Frankfurter Zeitung v. 6.6. u. 13. 6. 1909.
42.Darwin als Begründer der Descendenztheorie. - Der Monismus, 4, 49-54, Berlin 1909.
43.Ernst Haeckel. Versuch einer Chronik seines Lebens und Wirkens. - 301 S., Leipzig 1909.
44.Korallen und andere gesteinsbildende Tiere. - 122 S., Leipzig 1909.
45.Charles und Erasmus Darwin. - Archiv Gesch. Naturw. Technik, 2,1-90, Leipzig 1910.
46.Darwin und Patrick Matthew. - Zool. Annalen. Zeitschr. f. Gesch. d. Zoologie, 6, 280-295, Würzburg 1911.
47.Alexander von Humboldt und Charles Darwin. - 55 S., Brackwede u. Bielefeld 1911.
48.Die Caldera von La Palma. - Aus der Natur, 6, 685-691, Leipzig 1911.
49.Ernst Haeckel. - Westermanns Monatshefte, 109/2, 923-930, Braunschweig 1911.
50.Gomera, die Waldinsel der Kanaren. Reisetagebuch eines Zoologen. - Verh. Naturw. Ver. Karlsruhe, 24, 49-272, Karlsruhe 1912. (Besprechung: Karlsruher Zeitung v. 30. 5. 1912.)
51.Kants Stellung zum Deszendenzproblem. - Arch. Gesch. Naturw. Technik, 3,103-126, Leipzig 1912.
52.Herders Anschauung der organischen Natur. - Arch. Gesch. Naturw. Technik, 4, 8-39, 89-113, Leipzig 1913.
53.Große Biologen. Bilder aus der Geschichte der Biologie. VI. - 200 S., Leipzig u. Berlin 1914. (Besprechung: Literarisches Zentralblatt, 22, 1914).
54.Was Ernst Haeckel in meinem Leben bedeutet. — In: Was wir Ernst Haeckel verdanken I, 273-286, Leipzig 1914.
55.Biogenetische Mythen der Naturvölker. — Arch. Gesch. Naturw. Technik, 7, 68-77, Leipzig 1916.
56.Karl Vogt. — Westermanns Monatshefte, 61, 647-651, Braunschweig 1916/17.
57.Karl Vogt. — Die Umschau, 21, 525-529, Frankfurt a.M. 1917.
58.Karl Vogt's Bedeutung für Zoologie und Anthropologie. — Prometheus, 28, 610-613, Leipzig 1917.
59.Antike Vererbungstheorien. — Naturw. Wochenschrift, 16, 9-10, Jena 1917.
60.Kant und Herder als Vorläufer Weismann's. — Naturw. Wochenschrift, 16, 223-224, Jena 1917. 61.Ein neuer Beitrag zur Geschichte der Biographie. — Die Naturwissenschaften, 5, 36-39, Berlin 1917.
62.Lucrez und Darwin. — Die Naturwissenschaften, 5, 276-279, Berlin 1917.
63.Karl Vogt zu seinem 100. Geburtstag. — Die Naturwissenschaften, 5, 449-452, Berlin 1917.
64.Franz Wilhelm Junghuhn, ein Vorläufer Darwins. — Arch. Gesch. Naturw. Technik, 8, 182-186, Leipzig 1918.
65.Robinson. — Die Pyramide, Jg. 1919, 57-59, Karlsruhe 1919.
66.Robinson Crusoe. — Das politische Jahrhundert, 45, 5-7; 46, 5-7; 47, 6-8, Rastatt 1919. (Fragment im Besitz von Herrn H. MAY, Kassel. Es endet mit dem Vermerk „Forts. folgt". Diese ist jedoch in keiner Bibliothek der Bundesrepublik Deutschland nachweis-bar.)
Lectures in Karlsruhe
(N.V. = Naturwissenschaftlicher Verein, Karlsruhe)
------, 8. 11. Goethe und Alexander von Humboldt (zum Besten der Volksbibliothek des Badischen Frauenvereins, im Bibliothekssaal des Frauenvereins).
------, 10. 7. Darwin im Spiegel meines Lebens (Abdruck siehe Schriftenverzeichnis, Bespre-chung: Verh., 17, 6*, 1904).
------, 6. 5. Darwin und Haeckel (Jungliberaler Verein).
------, 1. 12. Schillers Verhältnis zur Natur und ihrer Wissenschaft (N.V., Besprechung: Verh., 19, 9*-10", 1906).
------, 23. 11. Die Naturteleologie und Biogenie der Kirchenväter (N.V., Abdruck siehe Schriftenverzeichnis).
------, 3. 7. Meine zoologische Studienreise nach den Kanarischen Inseln (N.V., Bespre-chung: Verh. 21, 29*-33*, 1909).
------, 25.11. Die Abstammung des Menschen (Deutscher Monistenbund).
------, 30.4. Darwin als Forscher und Mensch (N.V.).
------, 6. 12. Korallen und andere gesteinsbildende Tiere (Arbeiterbildungsverein).
------, 21. 10. Die Kanarische Insel La Palma (N.V., Besprechung: Verh. 24, 4*-7*, 1912).
------, 15. 12. Herders Anschauung der organischen Natur (N.V., Besprechung: Verh., 25, 6*-7*, 1913).
------, 4. 3. Meine Reise nach den Kanarischen Inseln im Winter 1907/08 (Arbeiterbildungs-verein).
------, 7.12. Tatsachen und Theorien der Vererbung (Deutscher Metallarbeiter-Verband, Ortsgruppe).
------, 22. 10. Tatsachen und Theorien der Vererbung (Verein für Volksbildung, Volkshoch-schulkurse).
Chronik der Haupt- und Residenzstadt Karlsruhe für das Jahr 1900-1913.
Chronik der Landeshauptstadt Karlsruhe für die Jahre 1918/19.
DEGENER, H. (1911-1922, 1928): Wer ist's? 5-8, Leipzig; 9, Berlin.
Fridericiana: Todesanzeige Walther May. — Karlsruher Zeitung, Bad. Staatsanzeiger v. 2. 12. 1926.
General-Anzeiger für Pforzheim und Umgebung v. 3. 1. 1903.
Gesamtverzeichnis des deutschsprachigen Schrifttums (GV) 1700-1910, 93, Mark-May, München / New York / London / Paris 1983.
HEILMANN, E. (1912): Geschichte der Arbeiterbewegung in Chemnitz und dem Erzgebirge. — 310 S., Chemnitz.
Karlsruher Tagblatt v. 4. 4. 1909. (Anzeige Darwin-Ausstellung).
Karlsruher Tagblatt v. 19. 11. 1921.
KÜRSCHNERS Deutscher Gelehrten-Kalender 1 u. 2, Berlin u. Leipzig 1925 u. 1926.
KÜRSCHNERS Deutscher Literatur-Kalender 32-40, auf das Jahr 1910-1922, Leipzig.
MAY, W. (1904): Darwin im Spiegel meines Lebens. — Verh. Naturw. Ver. Karlsruhe 17,1-32, Karlsruhe.
Nach der Schicht. — Zeitschrift des Krupp'schen Bildungsvereins Essen, 8/12, v. 15. 1. 1909.
Ortsgruppe Karlsruhe i. B. — Der Monismus, 3, 520, Berlin 1908.
SCHULZ, W. (1973): Bibliographie der badischen Geschichte, 6/2, Stuttgart.
USCHMANN, G. (1959): Geschichte der Zoologie und der zoologischen Anstalten in Jena 1779-1919. — 249 S., Jena.
WEIDNER, H. & WAGNER, W. (1968): Die entomologischen Sammlungen des Zoologischen Staatsinstituts und Zoologischen Museums Hamburg. VII, Insecta IV. — Mitt. Hamb. Zool. Mus. Inst., 65, 133-180, Hamburg.
Jena, Friedrich-Schiller-Universität, Institut für Geschichte der Medizin und der Naturwissenschaften — Ernst Haeckel-Haus: Briefe und Karten von MAY an HAECKEL, von HAECKEL an MAY, Von WALTHER an HAECKEL, Von NÜSSLIN an HAECKEL.
Karlsruhe, Badisches Generallandesarchiv: 235/2301 Dr. May, Walther Viktor.
Kassel, Familienarchiv Hellmut MAY: Skizzenbuch der Reise nach den Kanarischen Inseln von Klara MAY, Briefe von MAY an seine Mutter, seinen Bruder und seine Schwägerin.
I am indebted to the following people for information
Herr Prof. Dr. G. ABRAHAM, Hamburg; Herr Dr. ANDERNACHT, Frankfurt a.M.; Herr Dr. H. FRANKE, Jena; Frau M. Fuss, Baden-Baden; Herr Pastor GIESEN, Keitum; Herr GRUHL, Leipzig; Frau R. HOEVEL, Marburg; Herr Dr. K. Hot.; Berlin; Herr KLAUBE, Kassel; Frau Dr. E. KRAUSSE, Jena; Herr Dr. KRZEPINSKI, Emmendingen; Frau Dr. H. KUHN, Göttingen; Frau Dr. R. MAHLKE, Berlin; Herr H. MAY, Kassel; Rat der Stadt Karl-Marx-Stadt; Herr Dr. H. RÖSCH-SONDERMANN, Bonn; Herr Dr. V. WAHL, Jena.